89 lines
2.7 KiB
Markdown
89 lines
2.7 KiB
Markdown
# 性能基线测量
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> 对应计划 Phase C5：基于 TSC 的关键性能指标测量
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## 状态: ⬜ PENDING
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## 测量方法
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所有指标基于 TSC（Time Stamp Counter）：
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```c
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static inline u64 rdtsc(void) {
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u32 lo, hi;
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__asm__ volatile("rdtsc" : "=a"(lo), "=d"(hi));
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return ((u64)hi << 32) | lo;
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}
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```
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TSC 频率需先校准（PIT 100ms busy-wait 测量）：
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```c
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u64 tsc_freq; // Hz
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u64 calibrate_tsc(void) {
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u64 start = rdtsc();
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pit_busy_wait(100); // 100ms
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u64 end = rdtsc();
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return (end - start) * 10; // ×10 得到 Hz
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}
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```
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时间换算：`ms = (tsc_diff * 1000) / tsc_freq`
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## 基线指标
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| # | 指标 | 测量位置 | 基线目标 | 实测 | 状态 |
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|---|---|---|---|---|---|
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| P1 | UTSM 启动到 DSK SELFTEST | UTSM entry → DSK selftest pass | < 500ms (QEMU) | | ⬜ |
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| P2 | DSK 加载 shell.elf 时间 | FAT32 read + PIE load 包围 | < 200ms | | ⬜ |
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| P3 | DSK 加载 desktop.elf 时间 | 同上 | < 200ms | | ⬜ |
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| P4 | shell `ping 10.0.2.2` RTT | echo request → reply | < 10ms (user-net) | | ⬜ |
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| P5 | shell `linux ls` 完整 RTT | IPC exec round-trip | < 100ms (park-and-resume) | | ⬜ |
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| P6 | shell `run PING.ELF` 加载时间 | FAT32 read + PIE load | < 150ms | | ⬜ |
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| P7 | desktop 窗口拖动帧率 | 帧计数/TSC | 30+ FPS | | ⬜ |
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| P8 | `pe HELLO64.EXE` 加载+执行 | pe_service_run 包围 | < 50ms | | ⬜ |
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| P9 | `pe HELLO32.EXE` 加载+执行 | x86emu32 解释 | < 200ms | | ⬜ |
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| P10 | UTSM VMM self-test | vmm_init → vmm_self_test | < 50ms | | ⬜ |
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| P11 | Linux guest 启动到 park | vmlaunch → daemon HLT | < 3s (QEMU WHPX) | | ⬜ |
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| P12 | e1000 DHCP 完整耗时 | netman DHCP start → final rc | < 5s | | ⬜ |
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## 自动化测量
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在 dev_mode run_dev_tests 中追加性能测量代码：
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```c
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/* 在 run_dev_tests 开头校准 TSC */
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u64 tsc_freq = calibrate_tsc();
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logl("[shell] TSC freq: <Hz>");
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/* 各项测试包围 TSC */
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u64 t0 = rdtsc();
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/* ... 操作 ... */
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u64 t1 = rdtsc();
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u64 ms = (t1 - t0) * 1000 / tsc_freq;
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logl("[shell] perf: <name> = <ms>ms");
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```
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输出到串口日志，由 [ISO/run_tests.bat](../../ISO/run_tests.bat) 收集汇总。
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## 性能回归检测
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```powershell
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# 比较两次测试结果
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$prev = Get-Content ISO/logs/perf-baseline-prev.json | ConvertFrom-Json
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$curr = Get-Content ISO/logs/perf-baseline-curr.json | ConvertFrom-Json
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foreach ($m in $curr.metrics) {
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$p = $prev.metrics | Where-Object name -eq $m.name
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if ($p -and $m.ms -gt $p.ms * 1.5) {
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Write-Host "[REGRESSION] $($m.name): $($p.ms)ms -> $($m.ms)ms (>50%)"
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}
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}
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```
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## 已知限制
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- QEMU 性能数据不等于真机，仅作回归参考
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- WHPX vs TCG 性能差异巨大，必须固定加速方案
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- 多次测量取中位数，避免单次抖动
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