读取 systrace 日志答案

【问题标题】：Reading systrace log读取 systrace 日志
【发布时间】：2014-04-07 00:33:56
【问题描述】：

我知道之前有人问过这个问题，但我担心“systrace 使用扩展 ftrace 的 atrace，因此请在此处检查 ftrace 格式”对我来说还不够。我正在了解有关某些 systrace 特定标记/格式的更多详细信息。我有一些我没有信心的猜测，因此我需要真正了解它们的人来确认/否定。

这是我在 trace.html 中找到的一些结果。

# tracer: nop\n\
#\n\
# entries-in-buffer/entries-written: 393636/393636   #P:1\n\
#\n\
#                              _-----=> irqs-off\n\
#                             / _----=> need-resched\n\
#                            | / _---=> hardirq/softirq\n\
#                            || / _--=> preempt-depth\n\
#                            ||| /     delay\n\
#           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION\n\
#              | |       |   ||||       |         |\n\
          atrace-27768 [000] ...2 17184.509740: sched_switch: prev_comm=atrace prev_pid=27768 prev_prio=120 prev_state=S ==> next_comm=swapper/0 next_pid=0 next_prio=120\n\
      Thread-117-16753 [001] ...1 17184.510251: tracing_mark_write: B|4237|eglSwapBuffers\n\
          <idle>-0     [000] d.h4 17184.510329: sched_wakeup: comm=AudioOut_2 pid=608 prio=101 success=1 target_cpu=000\n\
          <idle>-0     [000] ...2 17184.510338: sched_switch: prev_comm=swapper/0 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=AudioOut_2 next_pid=608 next_prio=101\n\
      AudioOut_2-608   [000] d..4 17184.510393: sched_wakeup: comm=AudioTrack pid=16778 prio=104 success=1 target_cpu=000\n\
      AudioOut_2-608   [000] ...2 17184.510446: sched_switch: prev_comm=AudioOut_2 prev_pid=608 prev_prio=101 prev_state=S ==> next_comm=AudioTrack next_pid=16778 next_prio=104\n\
      Thread-117-16753 [001] ...1 17184.510610: tracing_mark_write: B|4237|queueBuffer\n\
      Thread-117-16753 [001] d..4 17184.510648: sched_wakeup: comm=Binder_2 pid=189 prio=120 success=1 target_cpu=001\n\
      Thread-117-16753 [001] ...2 17184.510656: sched_switch: prev_comm=Thread-117 prev_pid=16753 prev_prio=120 prev_state=R+ ==> next_comm=Binder_2 next_pid=189 next_prio=120\n\
        Binder_2-189   [001] ...2 17184.510664: sched_switch: prev_comm=Binder_2 prev_pid=189 prev_prio=120 prev_state=D ==> next_comm=Thread-117 next_pid=16753 next_prio=120\n\
      Thread-117-16753 [001] d..4 17184.510670: sched_wakeup: comm=Binder_2 pid=189 prio=120 success=1 target_cpu=001\n\
      Thread-117-16753 [001] ...2 17184.510673: sched_switch: prev_comm=Thread-117 prev_pid=16753 prev_prio=120 prev_state=R+ ==> next_comm=Binder_2 next_pid=189 next_prio=120\n\
        Binder_2-189   [001] ...1 17184.510722: tracing_mark_write: B|147|queueBuffer\n\
        Binder_2-189   [001] ...1 17184.510729: tracing_mark_write: B|147|SurfaceView: 0\n\
        Binder_2-189   [001] ...1 17184.510734: tracing_mark_write: E\n\
        Binder_2-189   [001] ...1 17184.510753: tracing_mark_write: C|147|SurfaceView|1\n\
        Binder_2-189   [001] d..4 17184.510772: sched_wakeup: comm=EventThread pid=255 prio=111 success=1 target_cpu=001\n\
        Binder_2-189   [001] ...1 17184.510781: tracing_mark_write: E\n\
        Binder_2-189   [001] ...2 17184.510810: sched_switch: prev_comm=Binder_2 prev_pid=189 prev_prio=120 prev_state=S ==> next_comm=EventThread next_pid=255 next_prio=111\n\
     EventThread-255   [001] d..4 17184.510828: sched_wakeup: comm=DispSync pid=186 prio=111 success=1 target_cpu=001\n\
     EventThread-255   [001] ...1 17184.510840: tracing_mark_write: C|147|VsyncOn|1\n\
     EventThread-255   [001] ...2 17184.510852: sched_switch: prev_comm=EventThread prev_pid=255 prev_prio=111 prev_state=S ==> next_comm=DispSync next_pid=186 next_prio=111\n\
        DispSync-186   [001] ...2 17184.510867: sched_switch: prev_comm=DispSync prev_pid=186 prev_prio=111 prev_state=S ==> next_comm=Thread-117 next_pid=16753 next_prio=120\n\
      Thread-117-16753 [001] ...1 17184.510885: tracing_mark_write: E\n\
      Thread-117-16753 [001] ...1 17184.510893: tracing_mark_write: B|4237|query\n\
      Thread-117-16753 [001] ...1 17184.510899: tracing_mark_write: E\n\
      Thread-117-16753 [001] ...1 17184.510906: tracing_mark_write: B|4237|query\n\
      Thread-117-16753 [001] ...1 17184.510911: tracing_mark_write: E\n\
      Thread-117-16753 [001] ...1 17184.510924: tracing_mark_write: E\n\
      AudioTrack-16778 [000] d.h7 17184.510984: sched_wakeup: comm=FastMixer pid=330 prio=96 success=1 target_cpu=000\n\
      AudioTrack-16778 [000] ...2 17184.511000: sched_switch: prev_comm=AudioTrack prev_pid=16778 prev_prio=104 prev_state=R+ ==> next_comm=FastMixer next_pid=330 next_prio=96\n\
      Thread-117-16753 [001] ...1 17184.511012: tracing_mark_write: B|4237|dequeueBuffer\n\
      Thread-117-16753 [001] d..4 17184.511034: sched_wakeup: comm=Binder_1 pid=185 prio=120 success=1 target_cpu=001\n\
      Thread-117-16753 [001] ...2 17184.511041: sched_switch: prev_comm=Thread-117 prev_pid=16753 prev_prio=120 prev_state=R+ ==> next_comm=Binder_1 next_pid=185 next_prio=120\n\
        Binder_1-185   [001] ...2 17184.511053: sched_switch: prev_comm=Binder_1 prev_pid=185 prev_prio=120 prev_state=D ==> next_comm=Thread-117 next_pid=16753 next_prio=120\n\
      Thread-117-16753 [001] d..4 17184.511059: sched_wakeup: comm=Binder_1 pid=185 prio=120 success=1 target_cpu=001\n\
      Thread-117-16753 [001] ...2 17184.511062: sched_switch: prev_comm=Thread-117 prev_pid=16753 prev_prio=120 prev_state=R+ ==> next_comm=Binder_1 next_pid=185 next_prio=120\n\
       FastMixer-330   [000] ...2 17184.511070: sched_switch: prev_comm=FastMixer prev_pid=330 prev_prio=96 prev_state=S ==> next_comm=AudioTrack next_pid=16778 next_prio=104\n\
      AudioTrack-16778 [000] ...2 17184.511087: sched_switch: prev_comm=AudioTrack prev_pid=16778 prev_prio=104 prev_state=S ==> next_comm=swapper/0 next_pid=0 next_prio=120\n\
        Binder_1-185   [001] ...1 17184.511093: tracing_mark_write: B|147|dequeueBuffer\n\
        Binder_1-185   [001] ...1 17184.511102: tracing_mark_write: B|147|SurfaceView: 1\n\
        Binder_1-185   [001] ...1 17184.511105: tracing_mark_write: E\n\
        Binder_1-185   [001] ...1 17184.511110: tracing_mark_write: E\n\
        Binder_1-185   [001] ...2 17184.511131: sched_switch: prev_comm=Binder_1 prev_pid=185 prev_prio=120 prev_state=S ==> next_comm=Thread-117 next_pid=16753 next_prio=120\n\
      Thread-117-16753 [001] ...1 17184.511143: tracing_mark_write: E\n\
          <idle>-0     [000] d.h4 17184.512011: sched_wakeup: comm=Thread-117 pid=16780 prio=120 success=1 target_cpu=000\n\
          <idle>-0     [000] ...2 17184.512021: sched_switch: prev_comm=swapper/0 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=Thread-117 next_pid=16780 next_prio=120\n\
      Thread-117-16780 [000] ...2 17184.512047: sched_switch: prev_comm=Thread-117 prev_pid=16780 prev_prio=120 prev_state=S ==> next_comm=swapper/0 next_pid=0 next_prio=120\n\
          <idle>-0     [000] d.h4 17184.513414: sched_wakeup: comm=Thread-117 pid=17201 prio=120 success=1 target_cpu=000\n\
          <idle>-0     [000] ...2 17184.513425: sched_switch: prev_comm=swapper/0 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=Thread-117 next_pid=17201 next_prio=120\n\
      Thread-117-17201 [000] ...2 17184.513441: sched_switch: prev_comm=Thread-117 prev_pid=17201 prev_prio=120 prev_state=S ==> next_comm=swapper/0 next_pid=0 next_prio=120\n\
      Thread-117-16753 [001] ...2 17184.516369: sched_switch: prev_comm=Thread-117 prev_pid=16753 prev_prio=120 prev_state=S ==> next_comm=swapper/1 next_pid=0 next_prio=120\n\
          <idle>-0     [000] d.h6 17184.517936: sched_wakeup: comm=kworker/0:3 pid=27267 prio=120 success=1 target_cpu=000\n\
          <idle>-0     [000] ...2 17184.517947: sched_switch: prev_comm=swapper/0 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=kworker/0:3 next_pid=27267 next_prio=120\n\
     kworker/0:3-27267 [000] ...2 17184.518045: sched_switch: prev_comm=kworker/0:3 prev_pid=27267 prev_prio=120 prev_state=S ==> next_comm=swapper/0 next_pid=0 next_prio=120\n\
          <idle>-0     [000] d.h7 17184.520977: sched_wakeup: comm=FastMixer pid=330 prio=96 success=1 target_cpu=000\n\
          <idle>-0     [000] ...2 17184.520986: sched_switch: prev_comm=swapper/0 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=FastMixer next_pid=330 next_prio=96\n\
       FastMixer-330   [000] ...2 17184.521041: sched_switch: prev_comm=FastMixer prev_pid=330 prev_prio=96 prev_state=S ==> next_comm=swapper/0 next_pid=0 next_prio=120\n\
          <idle>-0     [000] d.h6 17184.521117: sched_wakeup: comm=kworker/0:3 pid=27267 prio=120 success=1 target_cpu=000\n\
          <idle>-0     [000] ...2 17184.521122: sched_switch: prev_comm=swapper/0 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=kworker/0:3 next_pid=27267 next_prio=120\n\
     kworker/0:3-27267 [000] d..4 17184.521130: sched_wakeup: comm=hwc_eventmon pid=246 prio=100 success=1 target_cpu=000\n\
     kworker/0:3-27267 [000] ...2 17184.521135: sched_switch: prev_comm=kworker/0:3 prev_pid=27267 prev_prio=120 prev_state=S ==> next_comm=hwc_eventmon next_pid=246 next_prio=100\n\
    hwc_eventmon-246   [000] ...2 17184.521155: sched_switch: prev_comm=hwc_eventmon prev_pid=246 prev_prio=100 prev_state=S ==> next_comm=swapper/0 next_pid=0 next_prio=120\n\
          <idle>-0     [000] d.s5 17184.521414: sched_wakeup: comm=cfinteractive pid=88 prio=0 success=1 target_cpu=000\n\
          <idle>-0     [000] ...2 17184.521420: sched_switch: prev_comm=swapper/0 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=cfinteractive next_pid=88 next_prio=0\n\
   cfinteractive-88    [000] ...2 17184.521440: sched_switch: prev_comm=cfinteractive prev_pid=88 prev_prio=0 prev_state=S ==> next_comm=swapper/0 next_pid=0 next_prio=120\n\
          <idle>-0     [001] d.h4 17184.525814: sched_wakeup: comm=DispSync pid=186 prio=111 success=1 target_cpu=001\n\
          <idle>-0     [001] ...2 17184.525821: sched_switch: prev_comm=swapper/1 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=DispSync next_pid=186 next_prio=111\n\
        DispSync-186   [001] d..4 17184.525842: sched_wakeup: comm=EventThread pid=255 prio=111 success=1 target_cpu=001\n\
        DispSync-186   [001] ...2 17184.525851: sched_switch: prev_comm=DispSync prev_pid=186 prev_prio=111 prev_state=S ==> next_comm=EventThread next_pid=255 next_prio=111\n\
          <idle>-0     [000] d.h3 17184.525884: sched_wakeup: comm=surfaceflinger pid=147 prio=112 success=1 target_cpu=000\n\
          <idle>-0     [000] ...2 17184.525890: sched_switch: prev_comm=swapper/0 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=surfaceflinger next_pid=147 next_prio=112\n\
     EventThread-255   [001] ...2 17184.525892: sched_switch: prev_comm=EventThread prev_pid=255 prev_prio=111 prev_state=S ==> next_comm=swapper/1 next_pid=0 next_prio=120\n\

Q1：为什么“线程”带有不同的 PID，有时会被安排在不同的 CPU 上同时运行，例如线程 117？ “线程”在这里的真正含义是什么？

        Binder_1-185   [001] ...2 17184.511131: sched_switch: prev_comm=Binder_1 prev_pid=185 prev_prio=120 prev_state=S ==> next_comm=Thread-117 next_pid=16753 next_prio=120\n\
      Thread-117-16753 [001] ...1 17184.511143: tracing_mark_write: E\n\
          <idle>-0     [000] d.h4 17184.512011: sched_wakeup: comm=Thread-117 pid=16780 prio=120 success=1 target_cpu=000\n\
          <idle>-0     [000] ...2 17184.512021: sched_switch: prev_comm=swapper/0 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=Thread-117 next_pid=16780 next_prio=120\n\
      Thread-117-16780 [000] ...2 17184.512047: sched_switch: prev_comm=Thread-117 prev_pid=16780 prev_prio=120 prev_state=S ==> next_comm=swapper/0 next_pid=0 next_prio=120\n\

Q2：“sched_switch”中的“prev_state”是什么意思？这个变量中的“S,D,R,R+”分别指的是什么？

Q3：“tracing_mark_write”使用 B 表示开始，C 表示更改，E 表示结束。但是 E 标签不带有跟踪名称。如何确定它对应的是哪个B标签？它是否在调用堆栈样式 LIFO 中工作？如果是这样，那么只有当“线程”是一个无法拆分以在两个 CPU 上连贯地运行的真实线程时，才能保证这一点。这让我们回到了第一季度。

感谢任何帮助！

【问题讨论】：

标签： android systrace

【解决方案1】：

A1：它向您显示了您将从设备上的ps -t 看到的线程名称，该名称由进程设置。未命名的 Dalvik 线程被命名为“Thread-N”，其中 N 是 Thread 类跟踪的序列号（与 Binder 线程池创建“Binder_1”的方式相同）。所以“Thread-117”中的“117”与系统pid或tid没有关系；这就是线程的名称。它不能保证是唯一的——你可以在一个进程中拥有多个实例，也可以在不同的进程中。

A2：状态与您在ps 输出中看到的相同。请参阅 Linux 手册页的“过程状态代码”部分：

   D    uninterruptible sleep (usually IO)
   R    running or runnable (on run queue)
   S    interruptible sleep (waiting for an event to complete)
   ...

A3：是的，LIFO，用于单线程。这与公共android.os.Trace API 匹配。（"asynchronous" traces 有一个不同的（非公开的）API，您可以在其中为开始和结束提供相同的标签和“cookie”，但它没有被广泛使用。）

【讨论】：