简介
mem_stress.c — 内存加压
按入参大小mmap 一块匿名私有页 (MAP_PRIVATE|MAP_ANONYMOUS)，逐页写入触页提交物理内存，形成真实内存压力。
- 默认每页写 1 字节提交；
-f整块 memset -t sec保持时长（默认直到 SIGINT/SIGTERM）-k sec周期重触，对抗 XNU compressor / 鸿蒙 zram 压缩回收- iOS/macOS 额外打印
phys_footprint（jetsam 判定口径）
mem_bench.c — mmap/memset 耗时统计
按入参大小分轮申请匿名页，分别计时 mmap / 填充 / munmap，输出 avg/min/max 与吞吐。-m memset（默认）：整块填充 + MiB/s 吞吐-m touch：每页写 1 字节，输出 ns/page 首触缺页成本-m none：仅 mmap/munmap（映射建立成本）- 每轮换填充值 0x11/0x22… 并读回校验，防零页/去重优化
设计要点：纯 POSIX C、单文件、无第三方依赖，仅 RSS 读取按平台分支（Apple 走
task_vm_info，
Linux/鸿蒙走 /proc/self/statm）。大小参数支持 512M / 2G / 100K / KiB 二进制单位。
参数为手写解析（BSD/musl 的 getopt 不做 GNU 重排，"size 在前选项在后"会解析失败，已规避）。
用法与实测输出
mem_stress — 内存加压
# 提交 512M 匿名页, 保持 2s 后释放; 长时间加压建议加 -k 5 对抗压缩
./mem_stress 512M -t 2
./mem_stress 1500M -t 60 -k 5
macOS (Apple Silicon, 16K 页) 实测：
alloc : 536870912 bytes (512.00 MiB), 32768 page(s) x 16384 B, mmap 0.040 ms touch : 10% ( 51.20 MiB) elapsed 0.01 s ... touch : 99% ( 506.88 MiB) elapsed 0.09 s touch : touched 32768 pages (512.00 MiB) in 0.092 s [5580.1 MiB/s, 357.1K pages/s] rss : resident 229.52 MiB, phys_footprint 513.22 MiB hold : 2.000 s release: munmap ok, total 2.120 s, peak rss 233.16 MiB
注意上面
rss 229 MiB < phys_footprint 513 MiB —— 触页完成后压缩器已吃掉约一半驻留页，
而 phys_footprint 把已压缩脏页一并计入，才是 jetsam 眼中的真实压力。加压实验请看 footprint。
mem_bench — mmap / memset 耗时统计
# 256M 重复 3 轮, 统计 mmap/memset/unmap 耗时; -m touch 看单缺页成本
./mem_bench 256M -r 3
./mem_bench 256M -m touch
macOS 实测（memset 模式）：
target : 268435456 bytes (256.00 MiB), 16384 page(s) x 16384 B, mode=memset, runs=3 run 1/3: mmap= 1.0 us | fill(memset)= 65.330 ms ( 3918.6 MiB/s) | unmap= 3.712 ms | rss= 256.56 MiB run 2/3: mmap= 10.0 us | fill(memset)= 33.109 ms ( 7732.0 MiB/s) | unmap= 6.100 ms | rss= 256.80 MiB run 3/3: mmap= 10.0 us | fill(memset)= 35.269 ms ( 7258.5 MiB/s) | unmap= 3.870 ms | rss= 256.80 MiB ---- summary (3 runs, 256.00 MiB, memset mode) ---- mmap : avg 7.000 us | min 0.999 us | max 10.001 us fill : avg 44.569 ms | min 33.109 ms | max 65.330 ms unmap : avg 4.561 ms | min 3.712 ms | max 6.100 ms memset throughput: avg 6303.0 MiB/s over 3 run(s) peak rss: 256.80 MiB
首触缺页成本对比（-m touch）：
macOS (16K 页) : first-touch fault: avg 1492.7 ns/page over 3 run(s) Linux musl (4K页): first-touch fault: avg 1103.2 ns/page over 3 run(s)
mmap 本身只是建立映射（µs 级），真正的成本在填充阶段的缺页 + 写入 —— 两者分开计时，恰好回答"申请"与"提交"各自的耗时。
编译与部署
| 平台 | 命令 | 产物 |
|---|---|---|
| 本机 (macOS/Linux) | make | mem_stress / mem_bench |
| iOS (越狱) | make ios | ios/*.arm64 Mach-O |
| HarmonyOS | make ohos（需 OHOS NDK） | ohos/*.musl ELF |
iOS — 编译 + 越狱设备部署
make ios # 等价: xcrun -sdk iphoneos clang -arch arm64 -O2 -miphoneos-version-min=12.0 -o ios/mem_stress mem_stress.c # 部署 (iproxy 2222 → 设备 22, root/alpine) scp -P 2222 ios/mem_stress root@localhost:/var/mobile/ios_memslice/ ssh -p 2222 root@localhost \ '/usr/bin/ldid -S /var/mobile/ios_memslice/mem_stress && chmod +x /var/mobile/ios_memslice/mem_stress' ssh -p 2222 root@localhost '/var/mobile/ios_memslice/mem_stress 200M -t 10'
- 必须设备端
ldid -S签名：Mac 侧签完传上去会被 SIGKILL (rc=137) - 覆盖二进制先
rm再传，直接覆盖同样触发 rc=137 - sftp/scp 上传后必须
chmod +x；工具仅需普通 mmap，无需 entitlements - 非越狱 iOS 无法直接跑 CLI 二进制，同一份源码可嵌进 App target 编译
HarmonyOS — OHOS NDK 编译 + hdc 部署
make ohos # 等价 (OHOS_NATIVE 按实际安装路径调整): OHOS_NATIVE=/Applications/DevEco-Studio.app/Contents/sdk/default/openharmony/native $OHOS_NATIVE/llvm/bin/clang --target=aarch64-linux-ohos \ --sysroot=$OHOS_NATIVE/sysroot -O2 -o ohos/mem_stress mem_stress.c # 部署 (设备需开发者模式) hdc file send ohos/mem_stress /data/local/tmp/mem_stress hdc shell "chmod +x /data/local/tmp/mem_stress" hdc shell "/data/local/tmp/mem_stress 200M -t 10"
- 必须用 OHOS NDK 的 clang（链接 musl，动态链接器
/lib/ld-musl-aarch64.so.1）；glibc 交叉链产物设备上无法运行 - 模拟器 (x86_64)：
make ohos OHOS_TRIPLE=x86_64-linux-ohos - 鸿蒙存在 zram 压缩回收，长时间加压建议
-k 5重触
验证矩阵（2026-10 实测）
| 平台 | 编译 | 运行 |
|---|---|---|
| macOS (Apple Silicon, 16K 页) | ✅ -Wall -Wextra 零警告 | ✅ 全模式 + SIGTERM 干净退出 + 压缩行为观察 |
iOS arm64 (xcrun -sdk iphoneos clang) | ✅ 零警告, 纯 libSystem 符号 | ✅ 真机全模式验证 + 轻重载实验 (见实验报告) |
| Linux aarch64 glibc | ✅ 零警告 | ✅ 全模式（4K 页, /proc RSS） |
| Linux aarch64 musl（鸿蒙同族 libc） | ✅ 零警告 | ✅ 全模式 |
| HarmonyOS 真机 | 命令已给出（本机无 NDK/hdc） | 待设备 |
实验报告：轻重载内存压力下申请 200M / 500M 耗时对比
实验设计
- 设备: iPhone 12 Pro (iPhone13,3) · iOS 14.8.1 越狱 · 6GB · 16K 页 (200M = 12800 页)
- 自变量:
mem_stress -P 50ballast 阶梯加压 (0 → 3200M → 3600M → 4600M)，模拟真实负载的半随机可压缩数据 - 因变量:
mem_bench 200M -r 5的 mmap / 首触缺页 (touch) / memset 耗时 - 控制: 轻载与重载在同一启动会话内测量；ballast 全程带
-t死开关；vm_stat 实时监控 free 页；测后释放并复测基线排除热漂移
| ballast 模式 | WKdm 压缩比 | 系统行为 |
|---|---|---|
默认触页 / -f 模式填充 | ~1000:1 | 被 compressor 零成本吸收（2400M 只占 991 页），形不成压力 |
-P 50 半随机（本实验采用） | ~2:1~2.5:1 | 真实负载模型：压缩器持续工作但有余量，系统优雅降级 |
-R 全随机 | ~1:1 | 压缩器被塞满 → 守护进程饿死 → watchdog 内核 panic |
结果：申请 200M（12800 页）耗时对比
| 状态 | ballast | free 页 | mmap 耗时* | touch 首触 (纯申请) | vs 轻载 | memset 耗时 | vs 轻载 | memset 吞吐 |
|---|---|---|---|---|---|---|---|---|
| 轻载基线 | 0 | 110535 | 15.2 µs | 35.9 ms (2804 ns/页) | — | 45.4 ms | — | 4411 MiB/s |
| 重载-1 | 3200M | 9596 | 15.3 µs | 43.0 ms (3358 ns/页) | +19.8% | 47.2 ms | +4.1% | 4234 MiB/s |
| 重载-2 | 3600M | 6690 | 18.3 µs | 43.8 ms (3424 ns/页) | +22.1% | 47.8 ms | +5.3% | 4190 MiB/s |
| 重载-3 | 4600M | 7753 | 15.4 µs | 52.6 ms (4111 ns/页) | +46.6% | 51.5 ms | +13.6% | 3885 MiB/s |
| 恢复复测 | 0 | 240790 | 13.0 µs | 36.4 ms (2844 ns/页) | +1.4% | 43.9 ms | -3.2% | 4561 MiB/s |
* mmap 均值取 touch/memset 两种模式各 5 轮共 10 次测量； 全部 50+ 次测量落在 8~27µs，与压力水平无关。unmap 释放 5.3~20.5ms（重载下偶发尖峰）。
冷首轮尖峰：压力态下第一笔分配最贵 —— 重载-2 首轮 4356 ns/页 (+55%)，
重载-3 首轮 6995 ns/页 (+150%)；后续轮次系统已提前回收，回落到 3000~3600。
mmap 建映射耗时恒定 9~27µs（与压力无关，XNU 预留免费，成本全在首触缺页）。
补测：申请 500M（32000 页）轻重载对比
同协议重测（重载 = 3600M+1000M -P 50 双实例，测量起点 free=4398 页，略深于 200M 重载-3 的 7753）：
| 状态 | ballast | free 页 | mmap 耗时* | touch 首触 (纯申请) | vs 轻载 | memset 耗时 | vs 轻载 | memset 吞吐 |
|---|---|---|---|---|---|---|---|---|
| 轻载基线 | 0 | 213317 | 17.9 µs | 91.1 ms (2847 ns/页) | — | 114.1 ms | — | 4382 MiB/s |
| 重载 | 4600M | 4398 | 23.5 µs | 122.2 ms (3820 ns/页) | +34.2% | 117.6 ms | +3.0% | 4257 MiB/s |
| 恢复复测 | 0 | 260589 | 15.2 µs | 93.9 ms (2935 ns/页) | +3.1% | 115.5 ms | +1.2% | 4330 MiB/s |
* mmap 两模式均值，仍与压力无关；冷首轮 6518 ns/页 (208.6ms, +129%)， run2~5 回落 2988~3349；测量期间 compressions +53195 次（200M 实验同期约 +15k）。
跨尺寸对比：200M vs 500M
| 指标 | 200M (12800 页) | 500M (32000 页) | 解读 |
|---|---|---|---|
| 轻载单页成本 | 2804 ns/页 | 2847 ns/页 | 完全一致 —— 申请成本线性，无尺寸惩罚 |
| 重载均值增幅 | +46.6% | +34.2% | 500M 填充时长 2.5 倍，pageout 有更多"边填边回收"重叠时间，稳态反而更低 |
| 重载冷首轮 | +150% (6995) | +129% (6518) | 第一轮付清全部回收欠账，尖峰比例相当 |
| memset 重载增幅 | +13.6% | +3.0% | 流式写与回收重叠，带宽几乎不受影响 |
| unmap 释放 | ~7.7 ms | ~18 ms | ~38µs/MiB 线性，与压力基本无关 |
关键发现
- "申请 200M"的真实成本在首触缺页：中载 +20%、重载 +47%、冷首轮最高 +150%；memset 带宽只降 4~12%（流式写与回收重叠）。
- XNU 压缩器是压力球阀：
-P 50ballast 以 2:1~2.5:1 被持续吸收，4600M 负载下压缩器持有 2.62GiB 仍守住 free 目标线 —— 优雅降级，不会硬停滞。 - 悬崖在不可压缩数据：全随机（1:1 存储）塞满压缩器 → mediaserverd 饿死 180s → userspace watchdog 内核 panic → 设备重启丢越狱（panic 日志已归档）。
⚠ 实测事故（已成为设计准则）：实验早期用
-R 全随机 ballast 加压至 4600M，
10:11:13 内核 panic：userspace watchdog timeout: jailbreakd BSOD handler failed …
no successful checkins from com.apple.mediaserverd in 180 seconds（panic 时 free=2867 页、
compressorSize=291717 页=4.45GiB）。教训：压力实验用 -P 50 + 死开关 + free>2000 监控。
完整原始实验记录（508 行，含每一步 vm_stat 快照）
# 实验: 轻载 vs 重载内存压力下, 申请 200M 匿名页的耗时对比
# 设备: iPhone 12 Pro (iPhone13,3) iOS 14.8 Taurine, 6GB, 16K 页, 总页数 367104
# 工具: mem_bench 200M (touch=纯申请/首触缺页, memset=申请+整块写入)
# 协议: 轻载基线 -> ballast 阶梯加压(free 1000-2000 页区间) -> 重载测量 -> 释放恢复复测
# 时间: 2026-10-09 09:56:17
########## Phase A: 轻载基线 ##########
----- vm_stat (轻载, before) -----
Pages free: 86949.
Pages speculative: 58176.
File-backed pages: 90245.
Anonymous pages: 83116.
Pages stored in compressor: 0.
Pages occupied by compressor: 0.
Decompressions: 0.
Compressions: 0.
----- mem_bench 200M -r 5 -m touch (轻载) -----
target : 209715200 bytes (200.00 MiB), 12800 page(s) x 16384 B, mode=touch , runs=5
run 1/5: mmap= 10.0 us | fill(touch )= 38.013 ms ( 2969.8 ns/page) | unmap= 7.208 ms | rss= 202.44 MiB
run 2/5: mmap= 20.0 us | fill(touch )= 32.744 ms ( 2558.1 ns/page) | unmap= 7.053 ms | rss= 202.47 MiB
run 3/5: mmap= 15.0 us | fill(touch )= 37.463 ms ( 2926.8 ns/page) | unmap= 7.943 ms | rss= 202.47 MiB
run 4/5: mmap= 13.0 us | fill(touch )= 37.458 ms ( 2926.4 ns/page) | unmap= 7.808 ms | rss= 202.47 MiB
run 5/5: mmap= 14.0 us | fill(touch )= 37.731 ms ( 2947.7 ns/page) | unmap= 7.415 ms | rss= 202.47 MiB
---- summary (5 runs, 200.00 MiB, touch mode) ----
mmap : avg 14.400 us | min 10.000 us | max 20.000 us
fill : avg 36.682 ms | min 32.744 ms | max 38.013 ms
unmap : avg 7.485 ms | min 7.053 ms | max 7.943 ms
first-touch fault: avg 2865.8 ns/page over 5 run(s)
peak rss: 202.47 MiB
----- mem_bench 200M -r 5 -m memset (轻载) -----
target : 209715200 bytes (200.00 MiB), 12800 page(s) x 16384 B, mode=memset, runs=5
run 1/5: mmap= 11.0 us | fill(memset)= 47.219 ms ( 4235.6 MiB/s) | unmap= 8.542 ms | rss= 202.38 MiB
run 2/5: mmap= 19.0 us | fill(memset)= 43.310 ms ( 4617.9 MiB/s) | unmap= 5.603 ms | rss= 202.41 MiB
run 3/5: mmap= 24.0 us | fill(memset)= 44.220 ms ( 4522.8 MiB/s) | unmap= 7.398 ms | rss= 202.41 MiB
run 4/5: mmap= 23.0 us | fill(memset)= 46.967 ms ( 4258.3 MiB/s) | unmap= 8.162 ms | rss= 202.41 MiB
run 5/5: mmap= 26.0 us | fill(memset)= 46.333 ms ( 4316.6 MiB/s) | unmap= 8.050 ms | rss= 202.41 MiB
---- summary (5 runs, 200.00 MiB, memset mode) ----
mmap : avg 20.600 us | min 11.000 us | max 26.000 us
fill : avg 45.610 ms | min 43.310 ms | max 47.219 ms
unmap : avg 7.551 ms | min 5.603 ms | max 8.542 ms
memset throughput: avg 4390.2 MiB/s over 5 run(s)
peak rss: 202.41 MiB
----- vm_stat (轻载, after) -----
Pages free: 87049.
Pages speculative: 58022.
File-backed pages: 90091.
Anonymous pages: 83272.
Pages stored in compressor: 0.
Pages occupied by compressor: 0.
Decompressions: 0.
Compressions: 0.
########## Phase B: 阶梯加压 ##########
----- B1: ballast 2400M 启动 -----
PID=1516
Pages free: 6267.
Pages speculative: 342.
File-backed pages: 74790.
Anonymous pages: 232740.
Pages stored in compressor: 29.
Pages occupied by compressor: 16.
Compressions: 37.
1516 /var/mobile/ios_memslice/mem_stress
----- B2: ballast +1200M (累计 3600M) -----
PID=1516
PID=1551
Pages free: 8993.
Pages speculative: 115.
File-backed pages: 74228.
Anonymous pages: 233087.
Pages stored in compressor: 75055.
Pages occupied by compressor: 991.
Decompressions: 32.
Compressions: 75087.
1516 /var/mobile/ios_memslice/mem_stress
1551 /var/mobile/ios_memslice/mem_stress
----- B3: 压缩性 A/B 验证 (512M 模式 vs 512M 随机, 各保持 6s) -----
--- pattern 512M (每页1字节 0xA5) ---
touch : touched 32768 pages (512.00 MiB) in 0.116 s [4408.4 MiB/s, 282.1K pages/s]
rss : resident 514.39 MiB, phys_footprint 513.30 MiB
release: munmap ok, total 6.168 s, peak rss 514.41 MiB
--- random 512M (-R) ---
touch : filled(random) 32768 pages (512.00 MiB) in 0.372 s [1377.9 MiB/s, 88.2K pages/s]
rss : resident 514.39 MiB, phys_footprint 513.30 MiB
release: munmap ok, total 6.409 s, peak rss 514.41 MiB
----- B4: 清场 + 随机 ballast 2000M 起步 (-R 不可压缩) -----
Pages free: 41558.
File-backed pages: 74194.
Pages stored in compressor: 110720.
PID=1765
Pages free: 5651.
Pages speculative: 97.
File-backed pages: 74185.
Anonymous pages: 232525.
Pages stored in compressor: 206406.
Pages occupied by compressor: 1529.
Decompressions: 84.
Compressions: 206574.
1516 /var/mobile/ios_memslice/mem_stress
1551 /var/mobile/ios_memslice/mem_stress
1765 /var/mobile/ios_memslice/mem_stress
----- B5: 清掉旧 pattern ballast + 随机 ballast +600M (累计 2600M) -----
1765 /var/mobile/ios_memslice/mem_stress
1811
Pages free: 5175.
Pages speculative: 113.
File-backed pages: 74207.
Anonymous pages: 63779.
Pages stored in compressor: 178792.
Pages occupied by compressor: 170441.
Decompressions: 578.
Compressions: 383746.
----- B6: 随机 ballast +800M (累计 3400M) -----
1865
Pages free: 5756.
Pages speculative: 3989.
File-backed pages: 49673.
Anonymous pages: 44451.
Pages stored in compressor: 243078.
Pages occupied by compressor: 216900.
Decompressions: 4828.
Compressions: 452505.
----- B7: 随机 ballast +800M (累计 4200M) -----
1895
Pages free: 7303.
Pages speculative: 495.
File-backed pages: 18031.
Anonymous pages: 14997.
Pages stored in compressor: 285747.
Pages occupied by compressor: 275337.
Decompressions: 21682.
Compressions: 539908.
----- B8: 随机 ballast +400M (累计 4600M) -----
2189
Exception (client): Error reading SSH protocol banner
Traceback (most recent call last):
File "/Users/sched/Library/Python/3.9/lib/python/site-packages/paramiko/transport.py", line 2213, in _check_banner
buf = self.packetizer.readline(timeout)
File "/Users/sched/Library/Python/3.9/lib/python/site-packages/paramiko/packet.py", line 395, in readline
buf += self._read_timeout(timeout)
File "/Users/sched/Library/Python/3.9/lib/python/site-packages/paramiko/packet.py", line 665, in _read_timeout
raise EOFError()
EOFError
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/Users/sched/Library/Python/3.9/lib/python/site-packages/paramiko/transport.py", line 2029, in run
self._check_banner()
File "/Users/sched/Library/Python/3.9/lib/python/site-packages/paramiko/transport.py", line 2217, in _check_banner
raise SSHException(
paramiko.ssh_exception.SSHException: Error reading SSH protocol banner
Traceback (most recent call last):
File "/Users/sched/Library/Python/3.9/lib/python/site-packages/paramiko/transport.py", line 2213, in _check_banner
buf = self.packetizer.readline(timeout)
File "/Users/sched/Library/Python/3.9/lib/python/site-packages/paramiko/packet.py", line 395, in readline
buf += self._read_timeout(timeout)
File "/Users/sched/Library/Python/3.9/lib/python/site-packages/paramiko/packet.py", line 665, in _read_timeout
raise EOFError()
EOFError
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/Users/sched/Documents/workspace/mem_alloc_bench/run_on_device.py", line 43, in <module>
c = connect()
File "/Users/sched/Documents/workspace/mem_alloc_bench/run_on_device.py", line 16, in connect
c.connect("localhost", port=2222, username="root", password="alpine",
File "/Users/sched/Library/Python/3.9/lib/python/site-packages/paramiko/client.py", line 443, in connect
t.start_client(timeout=timeout)
File "/Users/sched/Library/Python/3.9/lib/python/site-packages/paramiko/transport.py", line 701, in start_client
raise e
File "/Users/sched/Library/Python/3.9/lib/python/site-packages/paramiko/transport.py", line 2029, in run
self._check_banner()
File "/Users/sched/Library/Python/3.9/lib/python/site-packages/paramiko/transport.py", line 2217, in _check_banner
raise SSHException(
paramiko.ssh_exception.SSHException: Error reading SSH protocol banner
########## [重启后正式实验 10:5x 起, panic 后同一启动会话] ##########
----- 前置: 系统状态 -----
10:58:04 up 0:47, 0 users, load average: 2.21, 5.08, 4.17
Pages free: 113701.
File-backed pages: 81616.
Pages stored in compressor: 0.
Compressions: 1781.
----- Phase A': 轻载基线 mem_bench 200M -r 5 -m touch -----
target : 209715200 bytes (200.00 MiB), 12800 page(s) x 16384 B, mode=touch , runs=5
run 1/5: mmap= 12.0 us | fill(touch )= 35.096 ms ( 2741.9 ns/page) | unmap= 7.420 ms | rss= 202.34 MiB
run 2/5: mmap= 15.0 us | fill(touch )= 35.847 ms ( 2800.5 ns/page) | unmap= 7.354 ms | rss= 202.38 MiB
run 3/5: mmap= 15.0 us | fill(touch )= 35.055 ms ( 2738.7 ns/page) | unmap= 7.656 ms | rss= 202.38 MiB
run 4/5: mmap= 18.0 us | fill(touch )= 36.559 ms ( 2856.2 ns/page) | unmap= 7.690 ms | rss= 202.38 MiB
run 5/5: mmap= 20.0 us | fill(touch )= 36.880 ms ( 2881.3 ns/page) | unmap= 8.315 ms | rss= 202.38 MiB
---- summary (5 runs, 200.00 MiB, touch mode) ----
mmap : avg 16.000 us | min 12.000 us | max 20.000 us
fill : avg 35.887 ms | min 35.055 ms | max 36.880 ms
unmap : avg 7.687 ms | min 7.354 ms | max 8.315 ms
first-touch fault: avg 2803.7 ns/page over 5 run(s)
peak rss: 202.38 MiB
----- Phase A': 轻载基线 mem_bench 200M -r 5 -m memset -----
target : 209715200 bytes (200.00 MiB), 12800 page(s) x 16384 B, mode=memset, runs=5
run 1/5: mmap= 11.0 us | fill(memset)= 45.899 ms ( 4357.4 MiB/s) | unmap= 8.661 ms | rss= 202.41 MiB
run 2/5: mmap= 15.0 us | fill(memset)= 46.542 ms ( 4297.2 MiB/s) | unmap= 8.125 ms | rss= 202.44 MiB
run 3/5: mmap= 18.0 us | fill(memset)= 44.581 ms ( 4486.2 MiB/s) | unmap= 8.013 ms | rss= 202.44 MiB
run 4/5: mmap= 9.0 us | fill(memset)= 44.412 ms ( 4503.3 MiB/s) | unmap= 7.889 ms | rss= 202.44 MiB
run 5/5: mmap= 19.0 us | fill(memset)= 45.345 ms ( 4410.6 MiB/s) | unmap= 7.734 ms | rss= 202.44 MiB
---- summary (5 runs, 200.00 MiB, memset mode) ----
mmap : avg 14.400 us | min 9.000 us | max 19.000 us
fill : avg 45.356 ms | min 44.412 ms | max 46.542 ms
unmap : avg 8.084 ms | min 7.734 ms | max 8.661 ms
memset throughput: avg 4410.9 MiB/s over 5 run(s)
peak rss: 202.44 MiB
----- vm_stat (轻载基线后) -----
Pages free: 110535.
File-backed pages: 81526.
Pages stored in compressor: 0.
Compressions: 1781.
----- B'1: ballast 1600M -P 50 (累计 1600M) -----
2090
Pages free: 14192.
Pages speculative: 49480.
File-backed pages: 79309.
Anonymous pages: 171566.
Pages stored in compressor: 0.
Pages occupied by compressor: 32.
Decompressions: 302.
Compressions: 1781.
----- B'2: ballast +400M (累计 2000M) -----
2120
Pages free: 9939.
Pages speculative: 40712.
File-backed pages: 69471.
Anonymous pages: 194349.
Pages stored in compressor: 0.
Pages occupied by compressor: 32.
Decompressions: 302.
Compressions: 1781.
----- B'3: ballast +400M (累计 2400M) -----
2161
Pages free: 7525.
Pages speculative: 15316.
File-backed pages: 68406.
Anonymous pages: 220178.
Pages stored in compressor: 0.
Pages occupied by compressor: 32.
Decompressions: 302.
Compressions: 1781.
----- B'4: ballast +400M (累计 2800M) -----
2199
Pages free: 8021.
Pages speculative: 376.
File-backed pages: 72520.
Anonymous pages: 228919.
Pages stored in compressor: 16209.
Pages occupied by compressor: 8373.
Decompressions: 340.
Compressions: 18030.
----- B'5: ballast +400M (累计 3200M, 上限) -----
2242
Pages free: 6670.
Pages speculative: 740.
File-backed pages: 72180.
Anonymous pages: 194349.
Pages stored in compressor: 75869.
Pages occupied by compressor: 41306.
Decompressions: 399.
Compressions: 77858.
5
########## Phase C': 重载(3200M ballast)下测量 ##########
----- vm_stat (重载, before) -----
Pages free: 9596.
Pages speculative: 856.
File-backed pages: 72311.
Anonymous pages: 194653.
Pages stored in compressor: 75721.
Pages occupied by compressor: 41234.
Decompressions: 486.
Compressions: 77858.
----- mem_bench 200M -r 5 -m touch (重载) -----
error: multiple sizes given ('200M' and '600')
----- vm_stat (touch 测量后) -----
Pages free: 9515.
Pages stored in compressor: 75721.
Decompressions: 486.
Compressions: 77858.
----- mem_bench 200M -r 5 -m memset (重载) -----
error: multiple sizes given ('200M' and '600')
----- vm_stat (重载, after) -----
Pages free: 6164.
File-backed pages: 72317.
Pages stored in compressor: 75721.
Pages occupied by compressor: 41234.
Decompressions: 486.
Compressions: 77858.
----- mem_bench 200M -r 5 -m touch (重载, 修正) -----
target : 209715200 bytes (200.00 MiB), 12800 page(s) x 16384 B, mode=touch , runs=5
run 1/5: mmap= 14.0 us | fill(touch )= 45.172 ms ( 3529.1 ns/page) | unmap= 20.535 ms | rss= 202.31 MiB
run 2/5: mmap= 14.0 us | fill(touch )= 40.470 ms ( 3161.7 ns/page) | unmap= 6.474 ms | rss= 202.34 MiB
run 3/5: mmap= 16.0 us | fill(touch )= 43.704 ms ( 3414.4 ns/page) | unmap= 7.773 ms | rss= 202.34 MiB
run 4/5: mmap= 16.0 us | fill(touch )= 38.578 ms ( 3013.9 ns/page) | unmap= 6.597 ms | rss= 202.34 MiB
run 5/5: mmap= 10.0 us | fill(touch )= 46.995 ms ( 3671.5 ns/page) | unmap= 7.320 ms | rss= 202.34 MiB
---- summary (5 runs, 200.00 MiB, touch mode) ----
mmap : avg 14.000 us | min 10.000 us | max 16.000 us
fill : avg 42.984 ms | min 38.578 ms | max 46.995 ms
unmap : avg 9.740 ms | min 6.474 ms | max 20.535 ms
first-touch fault: avg 3358.1 ns/page over 5 run(s)
peak rss: 202.34 MiB
----- mem_bench 200M -r 5 -m memset (重载, 修正) -----
target : 209715200 bytes (200.00 MiB), 12800 page(s) x 16384 B, mode=memset, runs=5
run 1/5: mmap= 10.0 us | fill(memset)= 47.213 ms ( 4236.1 MiB/s) | unmap= 7.066 ms | rss= 202.38 MiB
run 2/5: mmap= 13.0 us | fill(memset)= 46.587 ms ( 4293.0 MiB/s) | unmap= 6.873 ms | rss= 202.44 MiB
run 3/5: mmap= 21.0 us | fill(memset)= 47.779 ms ( 4185.9 MiB/s) | unmap= 7.179 ms | rss= 202.44 MiB
run 4/5: mmap= 23.0 us | fill(memset)= 47.336 ms ( 4225.1 MiB/s) | unmap= 7.643 ms | rss= 202.44 MiB
run 5/5: mmap= 16.0 us | fill(memset)= 47.274 ms ( 4230.7 MiB/s) | unmap= 8.002 ms | rss= 202.44 MiB
---- summary (5 runs, 200.00 MiB, memset mode) ----
mmap : avg 16.600 us | min 10.000 us | max 23.000 us
fill : avg 47.238 ms | min 46.587 ms | max 47.779 ms
unmap : avg 7.353 ms | min 6.873 ms | max 8.002 ms
memset throughput: avg 4234.2 MiB/s over 5 run(s)
peak rss: 202.44 MiB
----- vm_stat (重载测量后) -----
Pages free: 14876.
File-backed pages: 71159.
Pages stored in compressor: 84584.
Pages occupied by compressor: 46117.
Decompressions: 487.
Compressions: 86725.
----- B'6: 重启 ballast 为单实例 3600M -P 50 -t 600 -----
Pages free: 182382.
Pages stored in compressor: 2140.
--- 启动 3600M 单实例 ---
2380
Pages free: 6690.
Pages speculative: 869.
File-backed pages: 49623.
Anonymous pages: 241395.
Pages stored in compressor: 49426.
Pages occupied by compressor: 19671.
Decompressions: 88609.
Compressions: 222194.
########## Phase C'2: 重载-2 (3600M ballast) 下测量 ##########
----- mem_bench 200M -r 5 -m touch -----
target : 209715200 bytes (200.00 MiB), 12800 page(s) x 16384 B, mode=touch , runs=5
run 1/5: mmap= 10.0 us | fill(touch )= 55.757 ms ( 4356.0 ns/page) | unmap= 11.909 ms | rss= 202.38 MiB
run 2/5: mmap= 27.0 us | fill(touch )= 43.881 ms ( 3428.2 ns/page) | unmap= 6.828 ms | rss= 202.41 MiB
run 3/5: mmap= 16.0 us | fill(touch )= 43.631 ms ( 3408.7 ns/page) | unmap= 6.215 ms | rss= 202.41 MiB
run 4/5: mmap= 24.0 us | fill(touch )= 38.083 ms ( 2975.2 ns/page) | unmap= 6.152 ms | rss= 202.41 MiB
run 5/5: mmap= 18.0 us | fill(touch )= 37.786 ms ( 2952.0 ns/page) | unmap= 5.731 ms | rss= 202.41 MiB
---- summary (5 runs, 200.00 MiB, touch mode) ----
mmap : avg 19.000 us | min 10.000 us | max 27.000 us
fill : avg 43.828 ms | min 37.786 ms | max 55.757 ms
unmap : avg 7.367 ms | min 5.731 ms | max 11.909 ms
first-touch fault: avg 3424.0 ns/page over 5 run(s)
peak rss: 202.41 MiB
----- mem_bench 200M -r 5 -m memset -----
target : 209715200 bytes (200.00 MiB), 12800 page(s) x 16384 B, mode=memset, runs=5
run 1/5: mmap= 11.0 us | fill(memset)= 46.442 ms ( 4306.4 MiB/s) | unmap= 7.360 ms | rss= 202.31 MiB
run 2/5: mmap= 24.0 us | fill(memset)= 47.410 ms ( 4218.5 MiB/s) | unmap= 7.586 ms | rss= 202.34 MiB
run 3/5: mmap= 14.0 us | fill(memset)= 50.152 ms ( 3987.9 MiB/s) | unmap= 7.843 ms | rss= 202.34 MiB
run 4/5: mmap= 19.0 us | fill(memset)= 48.134 ms ( 4155.1 MiB/s) | unmap= 7.731 ms | rss= 202.34 MiB
run 5/5: mmap= 20.0 us | fill(memset)= 46.689 ms ( 4283.7 MiB/s) | unmap= 7.863 ms | rss= 202.34 MiB
---- summary (5 runs, 200.00 MiB, memset mode) ----
mmap : avg 17.600 us | min 11.000 us | max 24.000 us
fill : avg 47.765 ms | min 46.442 ms | max 50.152 ms
unmap : avg 7.677 ms | min 7.360 ms | max 7.863 ms
memset throughput: avg 4190.3 MiB/s over 5 run(s)
peak rss: 202.34 MiB
----- vm_stat (重载-2 测量后) -----
Pages free: 14969.
File-backed pages: 43427.
Pages stored in compressor: 53622.
Pages occupied by compressor: 21995.
Decompressions: 88635.
Compressions: 226418.
----- B'7: 重启为 3600M + 1000M 双实例 (累计 4600M) -----
2489
--- +1000M ---
2511
Pages free: 7753.
Pages speculative: 749.
File-backed pages: 33222.
Anonymous pages: 198043.
Pages stored in compressor: 156749.
Pages occupied by compressor: 78372.
Decompressions: 99552.
Compressions: 353515.
########## Phase C'3: 重载-3 (4600M ballast, 压缩器持有 2.39G) 下测量 ##########
----- mem_bench 200M -r 5 -m touch -----
target : 209715200 bytes (200.00 MiB), 12800 page(s) x 16384 B, mode=touch , runs=5
run 1/5: mmap= 11.0 us | fill(touch )= 89.537 ms ( 6995.1 ns/page) | unmap= 13.056 ms | rss= 202.38 MiB
run 2/5: mmap= 22.0 us | fill(touch )= 42.230 ms ( 3299.2 ns/page) | unmap= 7.901 ms | rss= 202.44 MiB
run 3/5: mmap= 20.0 us | fill(touch )= 39.736 ms ( 3104.4 ns/page) | unmap= 7.672 ms | rss= 202.44 MiB
run 4/5: mmap= 17.0 us | fill(touch )= 46.354 ms ( 3621.4 ns/page) | unmap= 7.690 ms | rss= 202.44 MiB
run 5/5: mmap= 13.0 us | fill(touch )= 45.267 ms ( 3536.5 ns/page) | unmap= 6.450 ms | rss= 202.44 MiB
---- summary (5 runs, 200.00 MiB, touch mode) ----
mmap : avg 16.600 us | min 11.000 us | max 22.000 us
fill : avg 52.625 ms | min 39.736 ms | max 89.537 ms
unmap : avg 8.554 ms | min 6.450 ms | max 13.056 ms
first-touch fault: avg 4111.3 ns/page over 5 run(s)
peak rss: 202.44 MiB
----- mem_bench 200M -r 5 -m memset -----
target : 209715200 bytes (200.00 MiB), 12800 page(s) x 16384 B, mode=memset, runs=5
run 1/5: mmap= 11.0 us | fill(memset)= 53.629 ms ( 3729.3 MiB/s) | unmap= 6.615 ms | rss= 202.31 MiB
run 2/5: mmap= 18.0 us | fill(memset)= 51.653 ms ( 3872.0 MiB/s) | unmap= 7.813 ms | rss= 202.34 MiB
run 3/5: mmap= 12.0 us | fill(memset)= 49.734 ms ( 4021.4 MiB/s) | unmap= 7.805 ms | rss= 202.34 MiB
run 4/5: mmap= 12.0 us | fill(memset)= 53.077 ms ( 3768.1 MiB/s) | unmap= 7.610 ms | rss= 202.34 MiB
run 5/5: mmap= 18.0 us | fill(memset)= 49.575 ms ( 4034.3 MiB/s) | unmap= 7.287 ms | rss= 202.34 MiB
---- summary (5 runs, 200.00 MiB, memset mode) ----
mmap : avg 14.200 us | min 11.000 us | max 18.000 us
fill : avg 51.534 ms | min 49.575 ms | max 53.629 ms
unmap : avg 7.426 ms | min 6.615 ms | max 7.813 ms
memset throughput: avg 3885.0 MiB/s over 5 run(s)
peak rss: 202.34 MiB
----- vm_stat (重载-3 测量后) -----
Pages free: 15131.
File-backed pages: 32792.
Pages stored in compressor: 171828.
Pages occupied by compressor: 86710.
Decompressions: 100680.
Compressions: 369902.
########## Phase D: 释放 + 恢复复测 ##########
----- 释放全部 ballast -----
zsh:1: no matches found: [m]em_stress
killed
Pages free: 240790.
File-backed pages: 41256.
Pages stored in compressor: 41898.
Pages occupied by compressor: 15493.
----- 恢复后复测 mem_bench 200M -r 3 -m touch -----
target : 209715200 bytes (200.00 MiB), 12800 page(s) x 16384 B, mode=touch , runs=3
run 1/3: mmap= 10.0 us | fill(touch )= 38.698 ms ( 3023.3 ns/page) | unmap= 6.951 ms | rss= 202.38 MiB
run 2/3: mmap= 9.0 us | fill(touch )= 39.747 ms ( 3105.2 ns/page) | unmap= 6.099 ms | rss= 202.41 MiB
run 3/3: mmap= 8.0 us | fill(touch )= 30.754 ms ( 2402.7 ns/page) | unmap= 5.251 ms | rss= 202.41 MiB
---- summary (3 runs, 200.00 MiB, touch mode) ----
mmap : avg 9.000 us | min 8.000 us | max 10.000 us
fill : avg 36.400 ms | min 30.754 ms | max 39.747 ms
unmap : avg 6.100 ms | min 5.251 ms | max 6.951 ms
first-touch fault: avg 2843.7 ns/page over 3 run(s)
peak rss: 202.41 MiB
----- 恢复后复测 mem_bench 200M -r 3 -m memset -----
target : 209715200 bytes (200.00 MiB), 12800 page(s) x 16384 B, mode=memset, runs=3
run 1/3: mmap= 10.0 us | fill(memset)= 45.712 ms ( 4375.2 MiB/s) | unmap= 6.954 ms | rss= 202.38 MiB
run 2/3: mmap= 23.0 us | fill(memset)= 44.052 ms ( 4540.1 MiB/s) | unmap= 7.309 ms | rss= 202.41 MiB
run 3/3: mmap= 18.0 us | fill(memset)= 41.952 ms ( 4767.4 MiB/s) | unmap= 6.868 ms | rss= 202.41 MiB
---- summary (3 runs, 200.00 MiB, memset mode) ----
mmap : avg 17.000 us | min 10.000 us | max 23.000 us
fill : avg 43.905 ms | min 41.952 ms | max 45.712 ms
unmap : avg 7.044 ms | min 6.868 ms | max 7.309 ms
memset throughput: avg 4560.9 MiB/s over 3 run(s)
peak rss: 202.41 MiB
----- 最终 vm_stat -----
Pages free: 237475.
File-backed pages: 41256.
Pages stored in compressor: 41897.
Compressions: 369902.
########## 分析总结 (2026-10-09) ##########
# 设备: iPhone 12 Pro / iOS 14.8.1 / 6GB / 16K 页; mem_bench 200M = 12800 页
#
# | 状态 | ballast | free页 | mmap µs* | touch 首触 (纯申请) | vs轻载 | memset 耗时 | vs轻载 | memset MiB/s |
# |---------------|---------|---------|----------|------------------------|--------|-------------|--------|--------------|
# | 轻载基线 | 0 | 110535 | 15.2 | 35.9ms (2803.7 ns/页) | — | 45.4ms | — | 4410.9 |
# | 重载-1 | 3200M | 9596 | 15.3 | 43.0ms (3358.1 ns/页) | +19.8% | 47.2ms | +4.1% | 4234.2 |
# | 重载-2 | 3600M | 6690 | 18.3 | 43.8ms (3424.0 ns/页) | +22.1% | 47.8ms | +5.3% | 4190.3 |
# | 重载-3 | 4600M | 7753 | 15.4 | 52.6ms (4111.3 ns/页) | +46.6% | 51.5ms | +13.6% | 3885.0 |
# | 恢复复测 | 0 | 240790 | 13.0 | 36.4ms (2843.7 ns/页) | +1.4% | 43.9ms | -3.2% | 4560.9 |
# * mmap 为 touch/memset 两模式各 5 轮均值; 全部 50+ 次测量 8~27µs, 与压力无关
# unmap 释放 5.3~20.5ms (重载偶发尖峰)
#
# 冷启动首轮尖峰 (压力态下第一笔分配最贵):
# 重载-2 run1 = 4356 ns/page (+55%), 重载-3 run1 = 6995 ns/page (+150%)
# mmap 建映射耗时恒定 9~27us (与压力无关); unmap 5.3~20.5ms (重载偶发尖峰)
#
# 结论:
# 1. "申请200M"的真实成本在首触缺页: 中载+20%, 重载+47%, 冷首轮最高+150%
# 2. memset 带宽受影响较小 (-4%~-12%), 流式写与回收重叠
# 3. XNU 压缩器是压力球阀: -P 50 ballast 以 ~2:1~2.5:1 被持续吸收,
# 4600M 负载下仍守在 free_target 之上, 系统优雅降级
# 4. 悬崖: 不可压缩(随机)数据 1:1 塞满压缩器 -> 守护进程饿死 ->
# userspace watchdog 180s -> 内核 panic (10:11 事故, 见 INCIDENT-panic-1011.txt)
# 5. 加压实验设计准则: ballast 必须部分可压缩(-P 50≈真实App数据);
# 全随机=DoS, 模式填充=被零成本吸收
########## 补测实验: 申请 500M 轻重载对比 (2026-10-09 14:27 起, 与 200M 实验同一启动会话) ##########
----- Phase A-500: 轻载基线 mem_bench 500M -r 5 -m touch -----
target : 524288000 bytes (500.00 MiB), 32000 page(s) x 16384 B, mode=touch , runs=5
run 1/5: mmap= 11.0 us | fill(touch )= 93.043 ms ( 2907.6 ns/page) | unmap= 17.701 ms | rss= 502.44 MiB
run 2/5: mmap= 22.0 us | fill(touch )= 92.930 ms ( 2904.1 ns/page) | unmap= 17.845 ms | rss= 502.47 MiB
run 3/5: mmap= 23.0 us | fill(touch )= 86.046 ms ( 2688.9 ns/page) | unmap= 16.370 ms | rss= 502.47 MiB
run 4/5: mmap= 22.0 us | fill(touch )= 92.913 ms ( 2903.5 ns/page) | unmap= 19.712 ms | rss= 502.47 MiB
run 5/5: mmap= 8.0 us | fill(touch )= 90.540 ms ( 2829.4 ns/page) | unmap= 18.228 ms | rss= 502.47 MiB
---- summary (5 runs, 500.00 MiB, touch mode) ----
mmap : avg 17.200 us | min 8.000 us | max 23.000 us
fill : avg 91.094 ms | min 86.046 ms | max 93.043 ms
unmap : avg 17.971 ms | min 16.370 ms | max 19.712 ms
first-touch fault: avg 2846.7 ns/page over 5 run(s)
peak rss: 502.47 MiB
----- Phase A-500: 轻载基线 mem_bench 500M -r 5 -m memset -----
target : 524288000 bytes (500.00 MiB), 32000 page(s) x 16384 B, mode=memset, runs=5
run 1/5: mmap= 11.0 us | fill(memset)= 116.493 ms ( 4292.1 MiB/s) | unmap= 18.669 ms | rss= 502.38 MiB
run 2/5: mmap= 20.0 us | fill(memset)= 110.456 ms ( 4526.7 MiB/s) | unmap= 18.707 ms | rss= 502.41 MiB
run 3/5: mmap= 16.0 us | fill(memset)= 114.847 ms ( 4353.6 MiB/s) | unmap= 18.936 ms | rss= 502.41 MiB
run 4/5: mmap= 19.0 us | fill(memset)= 114.640 ms ( 4361.5 MiB/s) | unmap= 18.365 ms | rss= 502.41 MiB
run 5/5: mmap= 27.0 us | fill(memset)= 114.301 ms ( 4374.4 MiB/s) | unmap= 18.904 ms | rss= 502.41 MiB
---- summary (5 runs, 500.00 MiB, memset mode) ----
mmap : avg 18.600 us | min 11.000 us | max 27.000 us
fill : avg 114.147 ms | min 110.456 ms | max 116.493 ms
unmap : avg 18.716 ms | min 18.365 ms | max 18.936 ms
memset throughput: avg 4381.7 MiB/s over 5 run(s)
peak rss: 502.41 MiB
----- vm_stat (500M 轻载基线后) -----
Pages free: 213317.
File-backed pages: 56968.
Pages stored in compressor: 33760.
Compressions: 370147.
----- B-500: ballast 3600M + 1000M -P 50 -t 600 (累计 4600M, 同 200M 实验重载-3) -----
9393
--- +1000M ---
9418
Pages free: 4398.
Pages speculative: 239.
File-backed pages: 32916.
Anonymous pages: 196860.
Pages stored in compressor: 158699.
Pages occupied by compressor: 79841.
Decompressions: 112266.
Compressions: 497542.
########## Phase C-500: 重载 (4600M ballast, free 4398) 下测 500M ##########
----- mem_bench 500M -r 5 -m touch -----
target : 524288000 bytes (500.00 MiB), 32000 page(s) x 16384 B, mode=touch , runs=5
run 1/5: mmap= 12.0 us | fill(touch )= 208.561 ms ( 6517.5 ns/page) | unmap= 19.378 ms | rss= 501.69 MiB
run 2/5: mmap= 55.0 us | fill(touch )= 95.625 ms ( 2988.3 ns/page) | unmap= 17.797 ms | rss= 501.80 MiB
run 3/5: mmap= 34.0 us | fill(touch )= 101.681 ms ( 3177.5 ns/page) | unmap= 18.848 ms | rss= 501.80 MiB
run 4/5: mmap= 21.0 us | fill(touch )= 107.164 ms ( 3348.9 ns/page) | unmap= 20.622 ms | rss= 501.80 MiB
run 5/5: mmap= 24.0 us | fill(touch )= 98.115 ms ( 3066.1 ns/page) | unmap= 21.258 ms | rss= 501.80 MiB
---- summary (5 runs, 500.00 MiB, touch mode) ----
mmap : avg 29.200 us | min 12.000 us | max 55.000 us
fill : avg 122.229 ms | min 95.625 ms | max 208.561 ms
unmap : avg 19.581 ms | min 17.797 ms | max 21.258 ms
first-touch fault: avg 3819.7 ns/page over 5 run(s)
peak rss: 502.41 MiB
----- mem_bench 500M -r 5 -m memset -----
target : 524288000 bytes (500.00 MiB), 32000 page(s) x 16384 B, mode=memset, runs=5
run 1/5: mmap= 12.0 us | fill(memset)= 116.955 ms ( 4275.1 MiB/s) | unmap= 18.962 ms | rss= 502.38 MiB
run 2/5: mmap= 30.0 us | fill(memset)= 111.624 ms ( 4479.3 MiB/s) | unmap= 20.174 ms | rss= 502.41 MiB
run 3/5: mmap= 14.0 us | fill(memset)= 120.215 ms ( 4159.2 MiB/s) | unmap= 21.319 ms | rss= 502.41 MiB
run 4/5: mmap= 19.0 us | fill(memset)= 121.361 ms ( 4119.9 MiB/s) | unmap= 18.992 ms | rss= 502.41 MiB
run 5/5: mmap= 14.0 us | fill(memset)= 117.598 ms ( 4251.8 MiB/s) | unmap= 21.719 ms | rss= 502.41 MiB
---- summary (5 runs, 500.00 MiB, memset mode) ----
mmap : avg 17.800 us | min 12.000 us | max 30.000 us
fill : avg 117.551 ms | min 111.624 ms | max 121.361 ms
unmap : avg 20.233 ms | min 18.962 ms | max 21.719 ms
memset throughput: avg 4257.1 MiB/s over 5 run(s)
peak rss: 502.41 MiB
----- vm_stat (500M 重载测量后) -----
Pages free: 34438.
File-backed pages: 30598.
Pages stored in compressor: 189999.
Pages occupied by compressor: 99181.
Decompressions: 119690.
Compressions: 550737.
########## Phase D-500: 释放 + 恢复复测 ##########
zsh:1: no matches found: [m]em_stress
Pages free: 260589.
File-backed pages: 30729.
Pages stored in compressor: 30349.
----- 恢复后复测 mem_bench 500M -r 3 -m touch -----
target : 524288000 bytes (500.00 MiB), 32000 page(s) x 16384 B, mode=touch , runs=3
run 1/3: mmap= 11.0 us | fill(touch )= 90.145 ms ( 2817.0 ns/page) | unmap= 18.017 ms | rss= 502.38 MiB
run 2/3: mmap= 10.0 us | fill(touch )= 98.647 ms ( 3082.7 ns/page) | unmap= 18.167 ms | rss= 502.41 MiB
run 3/3: mmap= 17.0 us | fill(touch )= 92.975 ms ( 2905.5 ns/page) | unmap= 17.740 ms | rss= 502.41 MiB
---- summary (3 runs, 500.00 MiB, touch mode) ----
mmap : avg 12.667 us | min 10.000 us | max 17.000 us
fill : avg 93.922 ms | min 90.145 ms | max 98.647 ms
unmap : avg 17.975 ms | min 17.740 ms | max 18.167 ms
first-touch fault: avg 2935.1 ns/page over 3 run(s)
peak rss: 502.41 MiB
----- 恢复后复测 mem_bench 500M -r 3 -m memset -----
target : 524288000 bytes (500.00 MiB), 32000 page(s) x 16384 B, mode=memset, runs=3
run 1/3: mmap= 13.0 us | fill(memset)= 117.374 ms ( 4259.9 MiB/s) | unmap= 17.806 ms | rss= 502.31 MiB
run 2/3: mmap= 19.0 us | fill(memset)= 115.892 ms ( 4314.4 MiB/s) | unmap= 18.547 ms | rss= 502.34 MiB
run 3/3: mmap= 21.0 us | fill(memset)= 113.271 ms ( 4414.2 MiB/s) | unmap= 17.954 ms | rss= 502.34 MiB
---- summary (3 runs, 500.00 MiB, memset mode) ----
mmap : avg 17.667 us | min 13.000 us | max 21.000 us
fill : avg 115.512 ms | min 113.271 ms | max 117.374 ms
unmap : avg 18.102 ms | min 17.806 ms | max 18.547 ms
memset throughput: avg 4329.5 MiB/s over 3 run(s)
peak rss: 502.34 MiB
########## 500M 补测分析总结 ##########
# 协议与 200M 实验一致; 重载态 = 3600M+1000M -P 50 (同 200M 的重载-3), 测量起点 free=4398 (略深于上午的 7753)
#
# | 状态 | ballast | free页 | mmap µs* | touch 首触 (纯申请) | vs轻载 | memset 耗时 | vs轻载 | memset MiB/s |
# |----------|---------|---------|----------|-----------------------|--------|-------------|--------|--------------|
# | 轻载基线 | 0 | 213317 | 17.9 | 91.1ms (2846.7 ns/页) | — | 114.1ms | — | 4381.7 |
# | 重载 | 4600M | 4398 | 23.5 | 122.2ms (3819.7 ns/页)| +34.2% | 117.6ms | +3.0% | 4257.1 |
# | 恢复复测 | 0 | 260589 | 15.2 | 93.9ms (2935.1 ns/页) | +3.1% | 115.5ms | +1.2% | 4329.5 |
# * mmap 两模式均值; 500M 下全部测量 8~55µs 仍与压力无关 (重载 touch 模式一轮 55µs 为离群值)
#
# 冷首轮: 重载 run1 = 6517.5 ns/page (208.6ms, +129%); run2~5 回落 2988~3349 (系统提前回收)
# 测量期间 compressions +53195 次 (500M×5 轮强制回收, 200M 实验同期约 +15k)
#
# 跨尺寸对比 (轻载单页成本完全一致 -> 横向可比):
# 轻载 ns/页: 200M 2804 ≈ 500M 2847 (线性, 无尺寸惩罚)
# 重载均值 ns/页: 200M 4111 (+46.6%) > 500M 3820 (+34.2%)
# 重载冷首轮: 200M 6995 (+150%) ≈ 500M 6518 (+129%)
# memset 重载: 200M +13.6% > 500M +3.0%
# unmap: 200M ~7.7ms / 500M ~18ms (~38µs/MiB 线性, 与压力基本无关)
#
# 解释: 500M 单轮填充时长为 200M 的 2.5 倍, 给 pageout 更多"边填边回收"的重叠时间,
# 稳态均值反而更低; 但第一轮冷分配要付清全部欠账, 尖峰比例与 200M 相当。
########## run_case.sh 跨平台用例验证 (2026-10-09 15:0x, iOS 真机 dash) ##########
----- iOS 轻载 touch 64M x3 -----
CASE ts=2026-10-09T15:03:47+0800 platform=Darwin kernel=Darwin-20.6.0 arch=iPhone13,3 size_mib=64 mode=touch runs=3 ballast_mib=0 tool=mem_bench
PHASE name=case_start ts=2026-10-09T15:03:47+0800 pre_total=5735 pre_free=3851 pre_avail=-1 pre_free_spec=3958 pre_file=561 pre_anon=363 pre_swap_comp=380 pre_comp_occ=139
REC run=1 size_mib=64 mode=touch ballast_mib=0 mmap_us=10.0 fill_ms=10.484 unit=2559.6 unit_label=ns/page unmap_ms=0.977 rss_mib=66.39 pre_total=5735 pre_free=3851 pre_avail=-1 pre_free_spec=3958 pre_file=561 pre_anon=363 pre_swap_comp=380 pre_comp_occ=139
REC run=2 size_mib=64 mode=touch ballast_mib=0 mmap_us=15.0 fill_ms=11.910 unit=2907.7 unit_label=ns/page unmap_ms=1.538 rss_mib=66.39 pre_total=5735 pre_free=3905 pre_avail=-1 pre_free_spec=4012 pre_file=562 pre_anon=361 pre_swap_comp=380 pre_comp_occ=139
REC run=3 size_mib=64 mode=touch ballast_mib=0 mmap_us=10.0 fill_ms=12.455 unit=3040.8 unit_label=ns/page unmap_ms=0.903 rss_mib=66.42 pre_total=5735 pre_free=3905 pre_avail=-1 pre_free_spec=4012 pre_file=562 pre_anon=361 pre_swap_comp=380 pre_comp_occ=139
SUMMARY runs=3 fill_ms_avg=11.616 fill_ms_min=10.484 fill_ms_max=12.455
----- iOS 轻载 memset 64M x2 -----
CASE ts=2026-10-09T15:03:50+0800 platform=Darwin kernel=Darwin-20.6.0 arch=iPhone13,3 size_mib=64 mode=memset runs=2 ballast_mib=0 tool=mem_bench
PHASE name=case_start ts=2026-10-09T15:03:50+0800 pre_total=5735 pre_free=3905 pre_avail=-1 pre_free_spec=4012 pre_file=562 pre_anon=361 pre_swap_comp=380 pre_comp_occ=139
REC run=1 size_mib=64 mode=memset ballast_mib=0 mmap_us=10.0 fill_ms=14.360 unit=4456.8 unit_label=MiB/s unmap_ms=1.182 rss_mib=66.39 pre_total=5735 pre_free=3904 pre_avail=-1 pre_free_spec=4011 pre_file=562 pre_anon=361 pre_swap_comp=380 pre_comp_occ=139
REC run=2 size_mib=64 mode=memset ballast_mib=0 mmap_us=11.0 fill_ms=15.565 unit=4111.8 unit_label=MiB/s unmap_ms=1.326 rss_mib=66.39 pre_total=5735 pre_free=3904 pre_avail=-1 pre_free_spec=4011 pre_file=562 pre_anon=363 pre_swap_comp=380 pre_comp_occ=139
SUMMARY runs=2 fill_ms_avg=14.962 fill_ms_min=14.360 fill_ms_max=15.565
----- iOS 重载 touch 64M x2 -b 1200 -----
CASE ts=2026-10-09T15:03:52+0800 platform=Darwin kernel=Darwin-20.6.0 arch=iPhone13,3 size_mib=64 mode=touch runs=2 ballast_mib=1200 tool=mem_bench
PHASE name=case_start ts=2026-10-09T15:03:52+0800 pre_total=5735 pre_free=3904 pre_avail=-1 pre_free_spec=4011 pre_file=562 pre_anon=362 pre_swap_comp=380 pre_comp_occ=139
PHASE name=ballast_start ts=2026-10-09T15:03:52+0800 ballast_mib=1200 hold_s=900 pre_total=5735 pre_free=3904 pre_avail=-1 pre_free_spec=4011 pre_file=562 pre_anon=362 pre_swap_comp=380 pre_comp_occ=139
PHASE name=ballast_settled ts=2026-10-09T15:04:05+0800 waited_s=12 pid=10805 pre_total=5735 pre_free=2654 pre_avail=-1 pre_free_spec=2761 pre_file=562 pre_anon=1559 pre_swap_comp=380 pre_comp_occ=139
REC run=1 size_mib=64 mode=touch ballast_mib=1200 mmap_us=11.0 fill_ms=12.157 unit=2968.0 unit_label=ns/page unmap_ms=5.487 rss_mib=66.42 pre_total=5735 pre_free=2651 pre_avail=-1 pre_free_spec=2759 pre_file=562 pre_anon=1559 pre_swap_comp=380 pre_comp_occ=139
REC run=2 size_mib=64 mode=touch ballast_mib=1200 mmap_us=11.0 fill_ms=9.648 unit=2355.5 unit_label=ns/page unmap_ms=4.325 rss_mib=66.39 pre_total=5735 pre_free=2653 pre_avail=-1 pre_free_spec=2760 pre_file=562 pre_anon=1562 pre_swap_comp=380 pre_comp_occ=139
SUMMARY runs=2 fill_ms_avg=10.902 fill_ms_min=9.648 fill_ms_max=12.157
PHASE name=ballast_released ts=2026-10-09T15:04:06+0800 post_total=5735 post_free=3854 post_avail=-1 post_free_spec=3961 post_file=562 post_anon=361 post_swap_comp=380 post_comp_occ=139
其他原始数据下载： 设备功能验证日志 · panic 事故记录
平台须知
- 单位均为二进制：K=1024、M=1024²、G=1024³、T=1024⁴；大小自动向上取整到页
- iOS 单进程匿名保留上限 ~4GiB（14.8 实测：mmap 4G 成功 / 8G 失败），超限 mmap 直接报错；更常见的是压力过大先被 jetsam SIGKILL（属预期行为）
- iOS 极限加压（free 页 < 500）有内核 panic 风险，真机测试请留余量
- 信号处理：SIGINT/SIGTERM 干净退出并输出峰值 RSS；触页过程中断即时生效（
-f整块 memset 除外） - README 里有完整的坑清单与样例输出
源码
以下为完整源码（与服务端文件一致），右上角可复制 / 下载原始文件：
/*
* mem_stress.c — 匿名页内存加压工具 (iOS / HarmonyOS / macOS / Linux 通用)
*
* 功能:
* 按入参大小 mmap 一块匿名私有内存 (MAP_PRIVATE|MAP_ANONYMOUS), 并逐页写入
* 触页 (touch) 提交物理页, 形成真实内存压力; 之后按参数保持一段时间
* (或直到收到 SIGINT/SIGTERM) 再释放。
*
* 可选 -k 周期性重触: 每个周期向所有页写入新值, 迫使被 XNU compressor /
* Linux zram 压缩回收的页重新解压驻留, 并把干净页重新弄脏, 维持压力。
*
* 用法:
* mem_stress [-f|-R] [-k sec] [-t sec] [-qv] <size>[K|M|G|T]
* -R = 随机字节填充 (不可压缩, 模拟真实负载; 默认触页/0xA5 模式会被
* compressor 几乎零成本吸收, 无法形成持续压力)
*
* 构建:
* host : cc -O2 -o mem_stress mem_stress.c
* iOS : xcrun -sdk iphoneos clang -arch arm64 -O2 \
* -miphoneos-version-min=12.0 -o mem_stress mem_stress.c
* HarmonyOS : <OHOS_NDK>/llvm/bin/clang --target=aarch64-linux-ohos \
* --sysroot=<OHOS_NDK>/sysroot -O2 -o mem_stress mem_stress.c
*
* 说明:
* - 纯 POSIX C, 无第三方依赖; 仅 RSS/footprint 读取按平台分支。
* - 单位为二进制: K=1024, M=1024^2, G=1024^3, T=1024^4。
* - iOS 上单进程匿名保留有 ~4GiB 上限 (14.8 实测), 超限 mmap 直接失败;
* 更常见的是压力过大先被 jetsam 以 SIGKILL 终止 —— 属预期行为。
*/
#if !defined(__APPLE__)
#define _POSIX_C_SOURCE 200809L
#endif
#include <errno.h>
#include <inttypes.h>
#include <limits.h>
#include <signal.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/resource.h>
#include <time.h>
#include <unistd.h>
#if defined(__APPLE__)
#include <mach/mach.h>
#endif
#ifndef MAP_ANONYMOUS
#define MAP_ANONYMOUS MAP_ANON
#endif
static volatile sig_atomic_t g_stop = 0;
static size_t g_page = 4096;
/* ---------------- 公共小工具 ---------------- */
static void on_signal(int sig)
{
(void)sig;
g_stop = 1;
}
static double now_sec(void)
{
struct timespec ts;
clock_gettime(CLOCK_MONOTONIC, &ts);
return (double)ts.tv_sec + (double)ts.tv_nsec * 1e-9;
}
static double to_mib(unsigned long long bytes)
{
return (double)bytes / 1048576.0;
}
/*
* 解析大小参数: "1024" "100K" "512M" "2G" "1T", 兼容 B/iB 后缀与大小写。
* 二进制单位 (K=1024)。成功返回 0, 失败返回 -1。
*/
static int parse_size(const char *s, unsigned long long *out)
{
if (s == NULL || *s == '\0' || *s == '-' || *s == '+')
return -1;
errno = 0;
char *end = NULL;
unsigned long long v = strtoull(s, &end, 10);
if (errno != 0 || end == s)
return -1;
const char *u = end;
unsigned long long mult = 1ULL;
if (*u == 'K' || *u == 'k' || *u == 'M' || *u == 'm' ||
*u == 'G' || *u == 'g' || *u == 'T' || *u == 't') {
switch (*u | 0x20) {
case 'k': mult = 1ULL << 10; break;
case 'm': mult = 1ULL << 20; break;
case 'g': mult = 1ULL << 30; break;
case 't': mult = 1ULL << 40; break;
}
u++;
if (*u == 'i') /* KiB / MiB / GiB ... */
u++;
if (*u == 'B' || *u == 'b')
u++;
} else if (*u == 'B' || *u == 'b') {
u++; /* "100B" = 100 字节 */
}
if (*u != '\0')
return -1;
if (v == 0)
return -1;
if (v > ULLONG_MAX / mult)
return -1;
*out = v * mult;
return 0;
}
/* 当前驻留集 (字节); 取不到返回 0 (调用方按 0 跳过显示) */
static unsigned long long get_rss_bytes(void)
{
#if defined(__APPLE__)
struct task_vm_info vm;
mach_msg_type_number_t count = TASK_VM_INFO_COUNT;
if (task_info(mach_task_self(), TASK_VM_INFO,
(task_info_t)&vm, &count) != KERN_SUCCESS)
return 0;
return (unsigned long long)vm.resident_size;
#else
/* Linux / OpenHarmony(musl): /proc/self/statm 第二列 = 驻留页数 */
FILE *f = fopen("/proc/self/statm", "r");
if (f == NULL)
return 0;
unsigned long long total = 0, resident = 0;
int n = fscanf(f, "%llu %llu", &total, &resident);
fclose(f);
if (n != 2)
return 0;
return resident * (unsigned long long)g_page;
#endif
}
#if defined(__APPLE__)
/* iOS jetsam 的判定口径: phys_footprint = 驻留脏页 + 已压缩脏页 + IOKit 映射 */
static unsigned long long get_footprint_bytes(void)
{
struct task_vm_info vm;
mach_msg_type_number_t count = TASK_VM_INFO_COUNT;
if (task_info(mach_task_self(), TASK_VM_INFO,
(task_info_t)&vm, &count) != KERN_SUCCESS)
return 0;
return (unsigned long long)vm.phys_footprint;
}
#endif
/* 峰值驻留集 (字节); Darwin 的 ru_maxrss 单位是字节, Linux 系是 KiB */
static unsigned long long get_peak_rss_bytes(void)
{
struct rusage ru;
if (getrusage(RUSAGE_SELF, &ru) != 0)
return 0;
#if defined(__APPLE__)
return (unsigned long long)ru.ru_maxrss;
#else
return (unsigned long long)ru.ru_maxrss * 1024ULL;
#endif
}
/* xorshift64* 伪随机数: 填充不可压缩 ballast (随机数据 WKdm 压不动,
* 与 0xA5 模式填充不同, 无法被 compressor 几乎零成本地吸收) */
static uint64_t g_prng = 0;
static void prng_seed(uint64_t s)
{
g_prng = s ? s : 0x9E3779B97F4A7C15ULL;
}
static uint64_t prng_next(void)
{
uint64_t x = g_prng;
x ^= x << 13;
x ^= x >> 7;
x ^= x << 17;
g_prng = x;
return x * 0x2545F4914F6CDD1DULL;
}
/* 整块填充随机字节, 密度 pct (1..100): 每页前 pct% 为随机字节, 其余清零。
* pct=100 即全随机 (WKdm ~1:1, compressor 无净收益); pct=50 约 2:1 ——
* 接近真实 App 数据的压缩比, 可形成"压缩器仍有回收余量"的可持续重载。 */
static void fill_random(char *buf, size_t size, unsigned cycle, int pct)
{
prng_seed(0x9E3779B97F4A7C15ULL * (uint64_t)(cycle + 1) ^
(uint64_t)time(NULL) ^ (uint64_t)(uintptr_t)buf);
if (pct >= 100) {
size_t n64 = size / 8;
uint64_t *q = (uint64_t *)(void *)buf; /* mmap 区页对齐, 安全 */
for (size_t i = 0; i < n64; i++)
q[i] = prng_next();
for (size_t i = n64 * 8; i < size; i++)
buf[i] = (char)prng_next();
return;
}
/* 部分密度: 每页 [0, rand_bytes) 随机, 其余 0 */
size_t rand_bytes = (size_t)((unsigned long long)g_page * (unsigned)pct / 100);
if (rand_bytes == 0)
rand_bytes = 1;
memset(buf, 0, size);
for (size_t off = 0; off < size; off += g_page) {
size_t remain = rand_bytes;
if (off + remain > size)
remain = size - off;
size_t n64 = remain / 8;
uint64_t *q = (uint64_t *)(void *)(buf + off);
for (size_t i = 0; i < n64; i++)
q[i] = prng_next();
for (size_t i = n64 * 8; i < remain; i++)
buf[off + i] = (char)prng_next();
}
}
/*
* 解析秒数参数 (strtod 严格校验, 拒绝垃圾输入)。成功返回 0。
* 注: 不用 getopt —— BSD/musl 的 getopt 不重排 argv, "size 在前、选项在后"
* 的写法会解析失败; 手写解析保证各平台行为一致。
*/
static int parse_seconds(const char *s, double *out)
{
if (s == NULL || *s == '\0')
return -1;
errno = 0;
char *end = NULL;
double v = strtod(s, &end);
if (errno != 0 || end == s || *end != '\0' || v < 0.0)
return -1;
*out = v;
return 0;
}
static void usage(FILE *out, const char *prog)
{
fprintf(out,
"mem_stress - anonymous memory pressure tool (iOS/HarmonyOS/macOS/Linux)\n"
"\n"
"usage: %s [-f] [-k sec] [-t sec] [-qv] <size>\n"
"\n"
" <size> bytes of anonymous memory to commit\n"
" e.g. 268435456 | 100K | 512M | 1500M | 2G | 1T\n"
" (binary units: K=1024, M=1024^2, G=1024^3; B/iB suffix ok)\n"
" -f full fill: memset the whole region (default: 1 byte per page)\n"
" -R fill with pseudo-random bytes: incompressible ballast that\n"
" the compressor cannot absorb (realistic heavy load)\n"
" -P n partial random fill: first n%% of each page random, rest zero\n"
" (n=50 approximates real app data, ~2:1 WKdm ratio)\n"
" -k sec re-touch all pages every <sec> while holding, to defeat\n"
" compressor/zram reclaim (0 = off, default off)\n"
" -t sec hold duration after touch, then release\n"
" (default: hold until SIGINT/SIGTERM)\n"
" -q quiet (suppress progress lines)\n"
" -v verbose progress\n"
"\n"
"examples:\n"
" %s 512M -t 30 commit 512M, hold 30s, release\n"
" %s 1500M -t 60 -k 5 hold 60s, re-touch every 5s against compression\n"
" %s 2000M -R -t 900 incompressible ballast (heavy load emulation)\n",
prog, prog, prog, prog);
}
int main(int argc, char **argv)
{
int full_fill = 0, random_fill = 0, random_pct = 0, verbose = 0, quiet = 0;
double keep_interval = 0.0;
double hold_secs = -1.0; /* -1 = 一直持有直到信号 */
const char *size_arg = NULL;
for (int i = 1; i < argc; i++) {
const char *a = argv[i];
if (strcmp(a, "-f") == 0) {
full_fill = 1;
} else if (strcmp(a, "-R") == 0) {
random_fill = 1;
random_pct = 100;
} else if (strcmp(a, "-P") == 0) {
if (i + 1 >= argc) {
fprintf(stderr, "error: -P expects a percentage 1..100\n");
return 2;
}
i++;
long v = strtol(argv[i], NULL, 10);
if (v < 1 || v > 100 || argv[i][0] == '\0' ||
(strchr(argv[i], '-') != NULL)) {
fprintf(stderr, "error: -P expects a percentage 1..100\n");
return 2;
}
random_fill = 1;
random_pct = (int)v;
} else if (strcmp(a, "-q") == 0) {
quiet = 1;
} else if (strcmp(a, "-v") == 0) {
verbose = 1;
} else if (strcmp(a, "-h") == 0 || strcmp(a, "--help") == 0) {
usage(stdout, argv[0]);
return 0;
} else if (strcmp(a, "-k") == 0 || strcmp(a, "-t") == 0) {
double v = 0.0;
if (i + 1 >= argc || parse_seconds(argv[i + 1], &v) != 0) {
fprintf(stderr, "error: %s expects a non-negative number of seconds\n", a);
return 2;
}
i++;
if (a[1] == 'k')
keep_interval = v;
else
hold_secs = v;
} else if (a[0] == '-' && a[1] != '\0') {
fprintf(stderr, "error: unknown option '%s'\n", a);
usage(stderr, argv[0]);
return 2;
} else {
if (size_arg != NULL) {
fprintf(stderr, "error: multiple sizes given ('%s' and '%s')\n",
size_arg, a);
return 2;
}
size_arg = a;
}
}
if (size_arg == NULL) {
usage(stderr, argv[0]);
return 2;
}
unsigned long long req = 0;
if (parse_size(size_arg, &req) != 0) {
fprintf(stderr, "error: bad size '%s' (try 512M / 2G / 65536K)\n",
size_arg);
return 2;
}
long ps = sysconf(_SC_PAGESIZE);
if (ps > 0)
g_page = (size_t)ps;
if (req > (unsigned long long)(SIZE_MAX - (g_page - 1))) {
fprintf(stderr, "error: size %llu bytes exceeds this platform's address space\n",
req);
return 2;
}
size_t size = ((size_t)req + g_page - 1) & ~((size_t)g_page - 1);
unsigned long long pages = (unsigned long long)(size / g_page);
setvbuf(stdout, NULL, _IOLBF, 0); /* 管道/ssh 下进度实时可见 */
struct sigaction sa;
memset(&sa, 0, sizeof sa);
sa.sa_handler = on_signal;
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0; /* 不重启: nanosleep 被信号打断立刻返回 */
sigaction(SIGINT, &sa, NULL);
sigaction(SIGTERM, &sa, NULL);
double t_start = now_sec();
/* ---- 申请匿名区 ---- */
double t0 = now_sec();
char *mem = mmap(NULL, size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
double map_s = now_sec() - t0;
if (mem == MAP_FAILED) {
fprintf(stderr, "error: mmap %llu bytes failed: %s\n",
(unsigned long long)size, strerror(errno));
#if defined(__APPLE__)
fprintf(stderr, "hint: iOS caps a single process's anonymous reservation "
"(~4GiB observed on 14.8); try a smaller size.\n");
#endif
return 1;
}
if (!quiet)
printf("alloc : %llu bytes (%.2f MiB), %llu page(s) x %zu B, "
"mmap %.3f ms\n",
(unsigned long long)size, to_mib(size), pages, g_page,
map_s * 1e3);
/* ---- 触页提交物理内存 ---- */
unsigned long long done = 0; /* 已触页数 (page-touch 模式) */
t0 = now_sec();
if (random_fill) {
fill_random(mem, size, 0, random_pct); /* 密度见 -P/-R */
} else if (full_fill) {
memset(mem, 0xA5, size); /* 整块填充 (不可中途打断) */
} else {
/* 每页首字节写一次即触发缺页提交; 默认每 10% 汇报, -v 每 1% */
unsigned long long report_every = pages / (verbose ? 100 : 10);
if (report_every == 0)
report_every = 1;
for (size_t off = 0; off < size; off += g_page) {
if (g_stop)
break;
mem[off] = (char)0xA5;
done++;
if (!quiet && (done % report_every) == 0)
printf("touch : %3llu%% (%8.2f MiB) elapsed %.2f s\n",
done * 100ULL / pages,
to_mib(done * (unsigned long long)g_page),
now_sec() - t0);
}
}
double touch_s = now_sec() - t0;
if (g_stop && !full_fill && !random_fill) {
printf("touch : interrupted at %.2f MiB (%llu/%llu pages)\n",
to_mib(done * (unsigned long long)g_page), done, pages);
} else {
printf("touch : %s %llu pages (%.2f MiB) in %.3f s",
(random_fill || full_fill) ? "filled" : "touched",
pages, to_mib(size), touch_s);
if (random_fill)
printf(" [random %d%%/page]", random_pct);
if (touch_s > 0.0)
printf(" [%.1f MiB/s, %.1fK pages/s]",
to_mib(size) / touch_s,
(double)pages / touch_s / 1000.0);
printf("\n");
}
{
unsigned long long rss = get_rss_bytes();
#if defined(__APPLE__)
unsigned long long fp = get_footprint_bytes();
if (rss || fp)
printf("rss : resident %.2f MiB, phys_footprint %.2f MiB\n",
to_mib(rss), to_mib(fp));
#else
if (rss)
printf("rss : resident %.2f MiB\n", to_mib(rss));
#endif
}
/* ---- 保持 (可选周期重触) ---- */
if (!g_stop) {
if (hold_secs >= 0.0) {
if (!quiet)
printf("hold : %.3f s%s\n", hold_secs,
keep_interval > 0.0 ? ", re-touch on" : "");
} else if (!quiet) {
printf("hold : until SIGINT/SIGTERM (press Ctrl-C to release)\n");
}
double hold0 = now_sec();
double deadline = (hold_secs >= 0.0) ? hold0 + hold_secs : -1.0;
double next_cycle = (keep_interval > 0.0) ? hold0 + keep_interval : -1.0;
unsigned cycle = 0;
while (!g_stop) {
double now = now_sec();
if (deadline > 0.0 && now >= deadline)
break;
if (next_cycle > 0.0 && now >= next_cycle) {
cycle++;
/* 写入与上一周期不同的数据: 强制压缩页解压回 RAM、干净页重新变脏;
* -R 模式每轮换随机数据, 保持不可压缩 */
unsigned char pat = (unsigned char)(0xA0 | (cycle & 0x0F));
if (random_fill) {
fill_random(mem, size, cycle, random_pct);
} else if (full_fill) {
memset(mem, pat, size);
} else {
for (size_t off = 0; off < size && !g_stop; off += g_page)
mem[off] = (char)pat;
}
if (!quiet) {
printf("cycle : %u re-touched %.2f MiB", cycle, to_mib(size));
unsigned long long r2 = get_rss_bytes();
if (r2)
printf(", rss %.2f MiB", to_mib(r2));
printf("\n");
}
next_cycle += keep_interval;
continue;
}
struct timespec ts = { 0, 20 * 1000 * 1000 }; /* 20ms 轮询 */
nanosleep(&ts, NULL);
}
}
/* ---- 释放 ---- */
munmap(mem, size);
printf("release: munmap ok, total %.3f s, peak rss %.2f MiB\n",
now_sec() - t_start, to_mib(get_peak_rss_bytes()));
return 0;
}
/*
* mem_bench.c — 匿名页申请耗时基准 (iOS / HarmonyOS / macOS / Linux 通用)
*
* 功能:
* 按入参大小反复 mmap 一块匿名私有内存, 分别统计:
* - mmap 耗时 (建立映射本身, 通常只有 µs 级)
* - fill 耗时 (memset 整块填充 —— 真正触发缺页 + 写入的主成本;
* 或 touch 模式: 每页写 1 字节, 专门测首次触页缺页成本)
* - unmap 耗时 (munmap 释放)
* 每轮结束后做轻量读回校验 (防止填充被优化掉, 并确认内存真实可读),
* 最后输出 avg/min/max 汇总与吞吐率。
*
* 用法:
* mem_bench [-r n] [-m memset|touch|none] [-q] <size>[K|M|G|T]
*
* 构建:
* host : cc -O2 -o mem_bench mem_bench.c
* iOS : xcrun -sdk iphoneos clang -arch arm64 -O2 \
* -miphoneos-version-min=12.0 -o mem_bench mem_bench.c
* HarmonyOS : <OHOS_NDK>/llvm/bin/clang --target=aarch64-linux-ohos \
* --sysroot=<OHOS_NDK>/sysroot -O2 -o mem_bench mem_bench.c
*
* 说明:
* - 纯 POSIX C, 无第三方依赖; 仅 RSS 读取按平台分支。
* - 单位为二进制: K=1024, M=1024^2, G=1024^3, T=1024^4。
* - 每轮 memset 使用不同填充值 (0x11/0x22/...), 规避任何零页/去重优化。
* - iOS 为 16K 页, Linux/鸿蒙通常为 4K 页; touch 模式的 ns/page 指标
* 可直接对比两平台的单缺页成本。
*/
#if !defined(__APPLE__)
#define _POSIX_C_SOURCE 200809L
#endif
#include <errno.h>
#include <inttypes.h>
#include <limits.h>
#include <signal.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/resource.h>
#include <time.h>
#include <unistd.h>
#if defined(__APPLE__)
#include <mach/mach.h>
#endif
#ifndef MAP_ANONYMOUS
#define MAP_ANONYMOUS MAP_ANON
#endif
enum fill_mode { FILL_MEMSET, FILL_TOUCH, FILL_NONE };
static volatile sig_atomic_t g_stop = 0;
static volatile uint64_t g_sink = 0; /* 读回校验累加器, volatile 防优化 */
static size_t g_page = 4096;
/* ---------------- 公共小工具 ---------------- */
static void on_signal(int sig)
{
(void)sig;
g_stop = 1;
}
static double now_sec(void)
{
struct timespec ts;
clock_gettime(CLOCK_MONOTONIC, &ts);
return (double)ts.tv_sec + (double)ts.tv_nsec * 1e-9;
}
static double to_mib(unsigned long long bytes)
{
return (double)bytes / 1048576.0;
}
/* 解析大小参数 (与 mem_stress 相同: 二进制单位, 兼容 B/iB 后缀) */
static int parse_size(const char *s, unsigned long long *out)
{
if (s == NULL || *s == '\0' || *s == '-' || *s == '+')
return -1;
errno = 0;
char *end = NULL;
unsigned long long v = strtoull(s, &end, 10);
if (errno != 0 || end == s)
return -1;
const char *u = end;
unsigned long long mult = 1ULL;
if (*u == 'K' || *u == 'k' || *u == 'M' || *u == 'm' ||
*u == 'G' || *u == 'g' || *u == 'T' || *u == 't') {
switch (*u | 0x20) {
case 'k': mult = 1ULL << 10; break;
case 'm': mult = 1ULL << 20; break;
case 'g': mult = 1ULL << 30; break;
case 't': mult = 1ULL << 40; break;
}
u++;
if (*u == 'i')
u++;
if (*u == 'B' || *u == 'b')
u++;
} else if (*u == 'B' || *u == 'b') {
u++;
}
if (*u != '\0')
return -1;
if (v == 0)
return -1;
if (v > ULLONG_MAX / mult)
return -1;
*out = v * mult;
return 0;
}
/* 当前驻留集 (字节); 取不到返回 0 (调用方按 0 跳过显示) */
static unsigned long long get_rss_bytes(void)
{
#if defined(__APPLE__)
struct task_vm_info vm;
mach_msg_type_number_t count = TASK_VM_INFO_COUNT;
if (task_info(mach_task_self(), TASK_VM_INFO,
(task_info_t)&vm, &count) != KERN_SUCCESS)
return 0;
return (unsigned long long)vm.resident_size;
#else
FILE *f = fopen("/proc/self/statm", "r");
if (f == NULL)
return 0;
unsigned long long total = 0, resident = 0;
int n = fscanf(f, "%llu %llu", &total, &resident);
fclose(f);
if (n != 2)
return 0;
return resident * (unsigned long long)g_page;
#endif
}
/* 峰值驻留集 (字节); Darwin 的 ru_maxrss 单位是字节, Linux 系是 KiB */
static unsigned long long get_peak_rss_bytes(void)
{
struct rusage ru;
if (getrusage(RUSAGE_SELF, &ru) != 0)
return 0;
#if defined(__APPLE__)
return (unsigned long long)ru.ru_maxrss;
#else
return (unsigned long long)ru.ru_maxrss * 1024ULL;
#endif
}
/*
* 严格的整数解析 (拒绝垃圾输入)。注: 不用 getopt —— BSD/musl 的 getopt
* 不重排 argv, "size 在前、选项在后"的写法会解析失败; 手写解析保证
* 各平台行为一致。
*/
static int parse_int(const char *s, long *out)
{
if (s == NULL || *s == '\0')
return -1;
errno = 0;
char *end = NULL;
long v = strtol(s, &end, 10);
if (errno != 0 || end == s || *end != '\0')
return -1;
*out = v;
return 0;
}
static const char *fill_mode_name(enum fill_mode m)
{
switch (m) {
case FILL_MEMSET: return "memset";
case FILL_TOUCH: return "touch ";
case FILL_NONE: return "none ";
}
return "?";
}
static void usage(FILE *out, const char *prog)
{
fprintf(out,
"mem_bench - anonymous mmap/memset timing benchmark (iOS/HarmonyOS/macOS/Linux)\n"
"\n"
"usage: %s [-r n] [-m mode] [-q] <size>\n"
"\n"
" <size> bytes of anonymous memory per run\n"
" e.g. 268435456 | 100K | 512M | 2G (binary units, B/iB suffix ok)\n"
" -r n repeat runs (default 3)\n"
" -m mode fill mode after mmap (default memset):\n"
" memset memset the whole region (faults + bandwidth)\n"
" touch write 1 byte per page (first-touch fault cost, ns/page)\n"
" none mmap only (mapping setup/teardown cost)\n"
" -q quiet: per-run lines suppressed\n"
"\n"
"examples:\n"
" %s 512M -r 5 time mmap + memset of 512M, 5 runs\n"
" %s 512M -m touch time first-touch page faults (ns/page)\n",
prog, prog, prog);
}
/* 汇总打印一行: name avg/min/max (value 数组单位为秒, 乘 scale 换显示单位) */
static void print_stats(const char *name, const double *v, int n,
double scale, const char *unit)
{
double sum = 0.0, mn = v[0], mx = v[0];
for (int i = 0; i < n; i++) {
sum += v[i];
if (v[i] < mn) mn = v[i];
if (v[i] > mx) mx = v[i];
}
printf("%-7s: avg %10.3f %s | min %10.3f %s | max %10.3f %s\n",
name, sum / (double)n * scale, unit,
mn * scale, unit, mx * scale, unit);
}
int main(int argc, char **argv)
{
int repeats = 3;
int quiet = 0;
enum fill_mode mode = FILL_MEMSET;
const char *size_arg = NULL;
for (int i = 1; i < argc; i++) {
const char *a = argv[i];
if (strcmp(a, "-q") == 0) {
quiet = 1;
} else if (strcmp(a, "-h") == 0 || strcmp(a, "--help") == 0) {
usage(stdout, argv[0]);
return 0;
} else if (strcmp(a, "-r") == 0) {
long v = 0;
if (i + 1 >= argc || parse_int(argv[i + 1], &v) != 0 ||
v < 1 || v > 10000) {
fprintf(stderr, "error: -r expects an integer in 1..10000\n");
return 2;
}
i++;
repeats = (int)v;
} else if (strcmp(a, "-m") == 0) {
if (i + 1 >= argc) {
fprintf(stderr, "error: -m expects a mode (memset|touch|none)\n");
return 2;
}
i++;
if (strcmp(argv[i], "memset") == 0) mode = FILL_MEMSET;
else if (strcmp(argv[i], "touch") == 0) mode = FILL_TOUCH;
else if (strcmp(argv[i], "none") == 0) mode = FILL_NONE;
else {
fprintf(stderr, "error: unknown mode '%s' (memset|touch|none)\n",
argv[i]);
return 2;
}
} else if (a[0] == '-' && a[1] != '\0') {
fprintf(stderr, "error: unknown option '%s'\n", a);
usage(stderr, argv[0]);
return 2;
} else {
if (size_arg != NULL) {
fprintf(stderr, "error: multiple sizes given ('%s' and '%s')\n",
size_arg, a);
return 2;
}
size_arg = a;
}
}
if (size_arg == NULL) {
usage(stderr, argv[0]);
return 2;
}
unsigned long long req = 0;
if (parse_size(size_arg, &req) != 0) {
fprintf(stderr, "error: bad size '%s' (try 512M / 2G / 65536K)\n",
size_arg);
return 2;
}
long ps = sysconf(_SC_PAGESIZE);
if (ps > 0)
g_page = (size_t)ps;
if (req > (unsigned long long)(SIZE_MAX - (g_page - 1))) {
fprintf(stderr, "error: size %llu bytes exceeds this platform's address space\n",
req);
return 2;
}
size_t size = ((size_t)req + g_page - 1) & ~((size_t)g_page - 1);
unsigned long long pages = (unsigned long long)(size / g_page);
setvbuf(stdout, NULL, _IOLBF, 0);
struct sigaction sa;
memset(&sa, 0, sizeof sa);
sa.sa_handler = on_signal;
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
sigaction(SIGINT, &sa, NULL);
sigaction(SIGTERM, &sa, NULL);
double *t_mmap = malloc((size_t)repeats * sizeof(double));
double *t_fill = malloc((size_t)repeats * sizeof(double));
double *t_unmap = malloc((size_t)repeats * sizeof(double));
if (t_mmap == NULL || t_fill == NULL || t_unmap == NULL) {
fprintf(stderr, "error: out of memory\n");
return 1;
}
printf("target : %llu bytes (%.2f MiB), %llu page(s) x %zu B, "
"mode=%s, runs=%d\n",
(unsigned long long)size, to_mib(size), pages, g_page,
fill_mode_name(mode), repeats);
int completed = 0;
for (int i = 0; i < repeats && !g_stop; i++) {
/* --- mmap --- */
double t0 = now_sec();
char *p = mmap(NULL, size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
double t1 = now_sec();
if (p == MAP_FAILED) {
fprintf(stderr, "error: mmap %llu bytes failed on run %d: %s\n",
(unsigned long long)size, i + 1, strerror(errno));
#if defined(__APPLE__)
fprintf(stderr, "hint: iOS caps a single process's anonymous "
"reservation (~4GiB observed on 14.8); "
"try a smaller size.\n");
#endif
break;
}
t_mmap[i] = t1 - t0;
/* --- fill --- */
unsigned char pat = (unsigned char)(0x11 * (unsigned)(i + 1)); /* 0x11,0x22,... */
t0 = now_sec();
if (mode == FILL_MEMSET) {
memset(p, pat, size);
} else if (mode == FILL_TOUCH) {
for (size_t off = 0; off < size && !g_stop; off += g_page)
p[off] = (char)pat;
}
t1 = now_sec();
t_fill[i] = t1 - t0;
/* 轻量读回校验: 每页读首字节累加, 防止填充/映射被优化掉 */
if (mode != FILL_NONE) {
uint64_t sum = 0;
for (size_t off = 0; off < size; off += g_page)
sum += (uint64_t)(unsigned char)p[off];
g_sink = sum;
}
unsigned long long rss = get_rss_bytes();
/* --- unmap --- */
t0 = now_sec();
munmap(p, size);
t_unmap[i] = now_sec() - t0;
completed = i + 1;
if (!quiet) {
printf("run %d/%d: mmap=%9.1f us | fill(%s)=%10.3f ms",
i + 1, repeats, t_mmap[i] * 1e6,
mode == FILL_MEMSET ? "memset" :
mode == FILL_TOUCH ? "touch " : "none ",
t_fill[i] * 1e3);
if (mode == FILL_MEMSET && t_fill[i] > 0.0)
printf(" (%8.1f MiB/s)", to_mib(size) / t_fill[i]);
if (mode == FILL_TOUCH && t_fill[i] > 0.0 && pages > 0)
printf(" (%8.1f ns/page)",
t_fill[i] * 1e9 / (double)pages);
printf(" | unmap=%8.3f ms", t_unmap[i] * 1e3);
if (rss)
printf(" | rss=%8.2f MiB", to_mib(rss));
printf("\n");
}
if (i + 1 < repeats) {
struct timespec ts = { 0, 100 * 1000 * 1000 }; /* 100ms 间隔 */
nanosleep(&ts, NULL);
}
}
if (completed == 0) {
fprintf(stderr, "error: no run completed\n");
free(t_mmap); free(t_fill); free(t_unmap);
return 1;
}
/* ---- 汇总 ---- */
printf("---- summary (%d run%s, %.2f MiB, %s mode) ----\n",
completed, completed == 1 ? "" : "s", to_mib(size),
mode == FILL_MEMSET ? "memset" :
mode == FILL_TOUCH ? "touch" : "none");
print_stats("mmap", t_mmap, completed, 1e6, "us");
if (mode != FILL_NONE)
print_stats("fill", t_fill, completed, 1e3, "ms");
print_stats("unmap", t_unmap, completed, 1e3, "ms");
if (mode == FILL_MEMSET) {
double tp_sum = 0.0;
int tp_n = 0;
for (int i = 0; i < completed; i++) {
if (t_fill[i] > 0.0) {
tp_sum += to_mib(size) / t_fill[i];
tp_n++;
}
}
if (tp_n > 0)
printf("memset throughput: avg %.1f MiB/s over %d run(s)\n",
tp_sum / (double)tp_n, tp_n);
}
if (mode == FILL_TOUCH && pages > 0) {
double fp_sum = 0.0;
int fp_n = 0;
for (int i = 0; i < completed; i++) {
if (t_fill[i] > 0.0) {
fp_sum += t_fill[i] * 1e9 / (double)pages;
fp_n++;
}
}
if (fp_n > 0)
printf("first-touch fault: avg %.1f ns/page over %d run(s)\n",
fp_sum / (double)fp_n, fp_n);
}
printf("peak rss: %.2f MiB\n", to_mib(get_peak_rss_bytes()));
(void)g_sink;
free(t_mmap); free(t_fill); free(t_unmap);
return 0;
}
# mem_alloc_bench — 跨平台构建
#
# make 本机 (macOS/Linux) 编译 mem_stress + mem_bench
# make ios 交叉编译 iOS arm64 二进制 (输出到 ios/)
# make ohos 交叉编译 HarmonyOS arm64 二进制 (输出到 ohos/, 需 OHOS NDK)
# make clean
#
# OHOS NDK 路径按实际安装位置覆盖, 例如:
# make ohos OHOS_NATIVE=/path/to/openharmony/native
CC ?= cc
CFLAGS ?= -O2 -Wall -Wextra -std=c11
BINS = mem_stress mem_bench
# ---- iOS (Xcode 自带工具链) ----
IOS_CC := xcrun -sdk iphoneos clang
IOS_CFLAGS := -arch arm64 -O2 -Wall -Wextra -std=c11 -miphoneos-version-min=12.0
# ---- HarmonyOS (DevEco Studio 的 OHOS NDK, musl libc) ----
OHOS_NATIVE ?= /Applications/DevEco-Studio.app/Contents/sdk/default/openharmony/native
OHOS_CC := $(OHOS_NATIVE)/llvm/bin/clang
# 真机 arm64 用 aarch64-linux-ohos; 模拟器改 x86_64-linux-ohos
OHOS_TRIPLE ?= aarch64-linux-ohos
OHOS_CFLAGS := --target=$(OHOS_TRIPLE) --sysroot=$(OHOS_NATIVE)/sysroot \
-O2 -Wall -Wextra -std=c11
all: $(BINS)
mem_stress: mem_stress.c
$(CC) $(CFLAGS) -o $@ $<
mem_bench: mem_bench.c
$(CC) $(CFLAGS) -o $@ $<
ios: ios/mem_stress ios/mem_bench
ios/%: %.c
@mkdir -p ios
$(IOS_CC) $(IOS_CFLAGS) -o $@ $<
ohos: ohos/mem_stress ohos/mem_bench
ohos/%: %.c
@mkdir -p ohos
$(OHOS_CC) $(OHOS_CFLAGS) -o $@ $<
clean:
rm -rf $(BINS) ios ohos
.PHONY: all ios ohos clean
# mem_alloc_bench
两个纯 POSIX C 的匿名内存工具, 单文件、零依赖, 同一份源码可在
**iOS**(越狱设备) / **HarmonyOS** / macOS / Linux 上编译运行:
| 源码 | 功能 |
|---|---|
| `mem_stress.c` | 按入参大小 mmap 匿名页并逐页触页提交, 进行**内存加压**; 可选周期性重触对抗压缩回收, 可选保持时长后释放 |
| `mem_bench.c` | 按入参大小申请匿名页, 分轮统计 **mmap / 填充(memset) / munmap** 耗时, 输出 avg/min/max 与吞吐 |
## 用法
### mem_stress — 内存加压
```
usage: mem_stress [-f|-R|-P n] [-k sec] [-t sec] [-qv] <size>
<size> bytes of anonymous memory to commit
e.g. 268435456 | 100K | 512M | 1500M | 2G | 1T
(binary units: K=1024, M=1024^2, G=1024^3; B/iB suffix ok)
-f full fill: memset the whole region (default: 1 byte per page)
-R fill with pseudo-random bytes: incompressible ballast that
the compressor cannot absorb (WARNING: see 压力实验准则)
-P n partial random fill: first n% of each page random, rest zero
(n=50 approximates real app data, ~2:1 WKdm ratio)
-k sec re-touch all pages every <sec> while holding, to defeat
compressor/zram reclaim (0 = off, default off)
-t sec hold duration after touch, then release
(default: hold until SIGINT/SIGTERM)
-q quiet (suppress progress lines)
-v verbose progress
```
```console
$ ./mem_stress 512M -t 2
alloc : 536870912 bytes (512.00 MiB), 32768 page(s) x 16384 B, mmap 0.040 ms
touch : 10% ( 51.20 MiB) elapsed 0.01 s
...
touch : 99% ( 506.88 MiB) elapsed 0.09 s
touch : touched 32768 pages (512.00 MiB) in 0.092 s [5580.1 MiB/s, 357.1K pages/s]
rss : resident 229.52 MiB, phys_footprint 513.22 MiB
hold : 2.000 s
release: munmap ok, total 2.120 s, peak rss 233.16 MiB
```
要点:
- 默认**每页写 1 字节**触发缺页提交物理内存 (加压的标准姿势); `-f` 改为整块 memset。
- 默认**一直持有**直到 `Ctrl-C` / SIGTERM; `-t` 指定保持秒数。
- `-k sec` 周期性向所有页写入新值: 迫使被 XNU compressor / Linux zram 压缩的页
解压回 RAM、干净页重新变脏, 用于长时间维持真实压力。
- iOS/macOS 上额外打印 `phys_footprint` (jetsam 的判定口径, = 驻留脏页 + 已压缩脏页)。
上面真实样例里 RSS 229 MiB < footprint 513 MiB, 就是压缩器已经吃掉一部分页的
直接证据 —— 加压时看 footprint 才是真实压力。
### mem_bench — mmap / memset 耗时统计
```
usage: mem_bench [-r n] [-m mode] [-q] <size>
<size> bytes of anonymous memory per run
e.g. 268435456 | 100K | 512M | 2G (binary units, B/iB suffix ok)
-r n repeat runs (default 3)
-m mode fill mode after mmap (default memset):
memset memset the whole region (faults + bandwidth)
touch write 1 byte per page (first-touch fault cost, ns/page)
none mmap only (mapping setup/teardown cost)
-q quiet: per-run lines suppressed
```
```console
$ ./mem_bench 512M -r 3
target : 536870912 bytes (512.00 MiB), 32768 page(s) x 16384 B, mode=memset, runs=3
run 1/3: mmap= 3.0 us | fill(memset)= 82.261 ms ( 6221.3 MiB/s) | unmap= 8.328 ms | rss= 513.44 MiB
run 2/3: mmap= 5.0 us | fill(memset)= 55.465 ms ( 9231.9 MiB/s) | unmap= 5.724 ms | rss= 512.94 MiB
run 3/3: mmap= 12.0 us | fill(memset)= 42.753 ms ( 11975.5 MiB/s) | unmap= 5.822 ms | rss= 512.94 MiB
---- summary (3 runs, 512.00 MiB, memset mode) ----
mmap : avg 7.667 us | min 3.000 us | max 12.000 us
fill : avg 60.160 ms | min 42.753 ms | max 82.261 ms
unmap : avg 6.658 ms | min 5.724 ms | max 8.328 ms
memset throughput: avg 9143.6 MiB/s over 3 run(s)
peak rss: 512.78 MiB
```
要点:
- mmap 本身只是建立映射 (µs 级); 真正的成本在填充阶段 (缺页 + 写入),
两者分开计时, 恰好回答"申请"与"提交"各自的耗时。
- `-m touch` 每页只写 1 字节, 输出 **ns/page** —— 首次触页缺页的单页成本,
可直接对比 iOS (16K 页) 与鸿蒙 (4K 页) 平台。
- 每轮 memset 使用不同填充值 (0x11/0x22/…), 并做读回校验, 防止零页/去重类优化。
## 编译
### 本机 (macOS / Linux)
```console
$ make # 或 cc -O2 -o mem_stress mem_stress.c
$ ./mem_stress 512M -t 5
$ ./mem_bench 256M
```
### iOS (越狱设备, 无需 Xcode 工程)
```console
$ make ios # 产物在 ios/, arm64 Mach-O
# 等价命令:
$ xcrun -sdk iphoneos clang -arch arm64 -O2 -miphoneos-version-min=12.0 \
-o ios/mem_stress mem_stress.c
```
部署到设备 (iproxy 2222 → 设备 22, root/alpine):
```console
$ scp -P 2222 ios/mem_stress ios/mem_bench root@localhost:/var/mobile/ios_memslice/
$ ssh -p 2222 root@localhost \
'/usr/bin/ldid -S /var/mobile/ios_memslice/mem_stress && chmod +x /var/mobile/ios_memslice/mem_stress'
$ ssh -p 2222 root@localhost '/var/mobile/ios_memslice/mem_stress 200M -t 10'
```
注意 (2026-09 越狱设备实测的坑):
- **必须在设备端 `ldid -S` 签名**; Mac 侧 ldid 签完传上去会被 SIGKILL (rc=137)。
- **覆盖已有二进制必须先 `rm` 再传**, 直接覆盖同样触发 rc=137。
- `scp`/sftp 上传后必须 `chmod +x`。
- 本工具只需普通 mmap, 无需任何 entitlements。
- 非越狱 iOS 无法直接运行 CLI 二进制; 同一份源码可嵌进 App target 编译执行。
### HarmonyOS (DevEco Studio 的 OHOS NDK, musl libc)
```console
$ make ohos # 产物在 ohos/
# 等价命令 (OHOS_NATIVE 按实际安装路径调整):
$ OHOS_NATIVE=/Applications/DevEco-Studio.app/Contents/sdk/default/openharmony/native
$ $OHOS_NATIVE/llvm/bin/clang --target=aarch64-linux-ohos \
--sysroot=$OHOS_NATIVE/sysroot -O2 -o ohos/mem_stress mem_stress.c
```
部署到设备 (hdc, 设备需处于开发者模式):
```console
$ hdc file send ohos/mem_stress /data/local/tmp/mem_stress
$ hdc file send ohos/mem_bench /data/local/tmp/mem_bench
$ hdc shell "chmod +x /data/local/tmp/mem_stress /data/local/tmp/mem_bench"
$ hdc shell "/data/local/tmp/mem_stress 200M -t 10"
$ hdc shell "/data/local/tmp/mem_bench 256M -r 5"
```
注意:
- 必须用 **OHOS NDK 的 clang** (链接 musl, 动态链接器
`/lib/ld-musl-aarch64.so.1`); 普通 glibc 交叉链产物在设备上无法运行。
- 模拟器 (x86_64) 把 target 改为 `x86_64-linux-ohos`:
`make ohos OHOS_TRIPLE=x86_64-linux-ohos`。
- 鸿蒙内核同样存在 zram 压缩回收, 长时间加压建议加 `-k 5` 之类的重触选项。
## 验证状态 (2026-10 实测)
| 平台 | 编译 | 运行 |
|---|---|---|
| macOS (Apple Silicon, 16K 页) | ✅ `-Wall -Wextra` 零警告 | ✅ 全模式 + SIGTERM 干净退出 |
| iOS arm64 (`xcrun -sdk iphoneos clang`) | ✅ 零警告, 纯 libSystem 符号, 无需 entitlements | 待设备 (需越狱部署, 见上) |
| Linux aarch64 glibc (VM) | ✅ 零警告 | ✅ 全模式 (4K 页, /proc RSS) |
| Linux aarch64 **musl** (VM, 鸿蒙同族 libc) | ✅ 零警告 | ✅ 全模式 |
| HarmonyOS 真机 (OHOS NDK) | 命令已给出, 本机无 NDK/hdc | 待设备 |
## 已知平台行为
- **单位均为二进制**: K=1024, M=1024², G=1024³, T=1024⁴; 大小自动向上取整到页。
- **iOS 单进程匿名保留上限 ~4GiB** (iOS 14.8 实测: mmap 4G 成功 / 8G 失败),
超限 mmap 直接报错; 更常见的是压力过大先被 **jetsam SIGKILL** —— 属预期行为。
- iOS 极限加压 (free 页 < 500) 有内核 panic 风险, 手机上测试请留余量。
- macOS/Linux 上两者同样可用 (`make` 即可), 便于先在本机验证行为再到手机上跑。
## 压力实验准则 (2026-10-09 iPhone 12 Pro 6GB 实测教训)
在 iOS 上做内存压力实验, ballast 的**可压缩性**决定系统行为, 三种模式天差地别:
| ballast 模式 | WKdm 压缩比 | 系统行为 |
|---|---|---|
| 默认触页 / `-f` 模式填充 | ~1000:1 | 被 compressor 零成本吸收, **无法形成持续压力** |
| `-P 50` (半随机) | ~2:1~2.5:1 | **真实负载模型**: 压缩器持续工作但有余量, 系统优雅降级 |
| `-R` (全随机) | ~1:1 | 压缩器被塞满, 守护进程饿死 → **watchdog 内核 panic** |
实测事故: 4600M `-R` ballast → mediaserverd 180 秒无 checkin →
userspace watchdog panic → 设备重启丢越狱 (panic 日志归档于 raw-data/)。
做压力实验请用 `-P 50` + `-t` 死开关 + free 页实时监控 (保持 > 2000)。