Android Systrace 跟踪文件格式

Question

Android systrace工具，通过ADB调用atrace工具。但是，我不太了解跟踪文件的格式。显然它与 linux ftrace 工具非常相似，但有一些不同。主要区别在于它不使用 System.Map 文件，而是将所有信息包含到跟踪文件中。此外，还有特定于 android 的新 B|E 条目。

Android 源代码中有关于此格式的一些信息:http://androidxref.com/4.1.1/xref/external/chromium-trace/src/tracing/linux_perf_importer.js

但是，在该文档中我们可以读到该格式属于 Linux Perf 工具。我不这么认为，linux perf 作为输出提供了一种非常不同的格式...(除非某些特殊配置处于 Activity 状态...)

我的问题是:有人知道我在哪里可以找到关于使用来自 adb 的 atrace 工具生成的 android 跟踪文件的官方文档吗？

你熟悉这种格式吗？

# tracer: nop
#
# entries-in-buffer/entries-written: 66427/66427   #P:2
#
#                              _-----=> irqs-off
#                             / _----=> need-resched
#                            | / _---=> hardirq/softirq
#                            || / _--=> preempt-depth
#                            ||| /     delay
#           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
#              | |       |   ||||       |         |
          atrace-1724  [000] d..3 14186.680000: sched_switch: prev_comm=atrace prev_pid=1724 prev_prio=120 prev_state=S ==> next_comm=swapper/0 next_pid=0 next_prio=120
          <idle>-0     [000] d.h7 14186.690000: sched_wakeup: comm=tfm_b6bcf800 pid=1714 prio=35 success=1 target_cpu=000
          <idle>-0     [000] d..3 14186.690000: sched_switch: prev_comm=swapper/0 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=tfm_b6bcf800 next_pid=1714 next_prio=35
    tfm_b6bcf800-1714  [000] d..3 14186.690000: sched_switch: prev_comm=tfm_b6bcf800 prev_pid=1714 prev_prio=35 prev_state=D|W ==> next_comm=swapper/0 next_pid=0 next_prio=120
          <idle>-0     [001] d.h3 14186.690000: sched_wakeup: comm=Player Aud Mixe pid=146 prio=35 success=1 target_cpu=001
          <idle>-0     [001] d..3 14186.690000: sched_switch: prev_comm=swapper/1 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=Player Aud Mixe next_pid=146 next_prio=35
 Player Aud Mixe-146   [001] d..3 14186.690000: sched_switch: prev_comm=Player Aud Mixe prev_pid=146 prev_prio=35 prev_state=D ==> next_comm=swapper/1 next_pid=0 next_prio=120
          <idle>-0     [001] d.h3 14186.690000: sched_wakeup: comm=Player Aud Mixe pid=146 prio=35 success=1 target_cpu=001
          <idle>-0     [001] d..3 14186.690000: sched_switch: prev_comm=swapper/1 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=Player Aud Mixe next_pid=146 next_prio=35
 Player Aud Mixe-146   [001] d..3 14186.690000: sched_switch: prev_comm=Player Aud Mixe prev_pid=146 prev_prio=35 prev_state=S ==> next_comm=swapper/1 next_pid=0 next_prio=120
          <idle>-0     [001] d.h3 14186.700000: sched_wakeup: comm=Player Aud Mixe pid=146 prio=35 success=1 target_cpu=001
          <idle>-0     [001] d..3 14186.700000: sched_switch: prev_comm=swapper/1 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=Player Aud Mixe next_pid=146 next_prio=35
  EventThread-110   [001] d..5 14190.100000: sched_wakeup: comm=SurfaceFlinger pid=103 prio=112 success=1 target_cpu=001
     EventThread-110   [001] d..3 14190.100000: sched_switch: prev_comm=EventThread prev_pid=110 prev_prio=111 prev_state=S ==> next_comm=SurfaceFlinger next_pid=103 next_prio=112
  SurfaceFlinger-103   [001] ...1 14190.100000: tracing_mark_write: B|96|onMessageReceived
  SurfaceFlinger-103   [001] ...1 14190.100000: tracing_mark_write: B|96|handleTransaction
  SurfaceFlinger-103   [001] ...1 14190.100000: tracing_mark_write: B|96|doTransaction
  SurfaceFlinger-103   [001] ...1 14190.100000: tracing_mark_write: E
  SurfaceFlinger-103   [001] ...1 14190.100000: tracing_mark_write: E
  SurfaceFlinger-103   [001] ...1 14190.100000: tracing_mark_write: B|96|handleMessageInvalidate
  SurfaceFlinger-103   [001] ...1 14190.100000: tracing_mark_write: E
  SurfaceFlinger-103   [001] ...1 14190.100000: tracing_mark_write: E
  SurfaceFlinger-103   [001] ...1 14190.100000: tracing_mark_write: B|96|onMessageReceived
  SurfaceFlinger-103   [001] ...1 14190.100000: tracing_mark_write: B|96|handleMessageRefresh
  SurfaceFlinger-103   [001] ...1 14190.100000: tracing_mark_write: B|96|rebuildLayerStacks
  SurfaceFlinger-103   [001] ...1 14190.100000: tracing_mark_write: B|96|computeVisibleRegions
  SurfaceFlinger-103   [001] ...1 14190.100000: tracing_mark_write: E
  SurfaceFlinger-103   [001] ...1 14190.100000: tracing_mark_write: E
  SurfaceFlinger-103   [001] ...1 14190.100000: tracing_mark_write: B|96|doComposition
  SurfaceFlinger-103   [001] d.h4 14190.100000: sched_wakeup: comm=surfaceflinger pid=96 prio=120 success=1 target_cpu=001
  SurfaceFlinger-103   [001] d..3 14190.100000: sched_switch: prev_comm=SurfaceFlinger prev_pid=103 prev_prio=112 prev_state=R ==> next_comm=surfaceflinger next_pid=96 next_prio=120

提前致谢!

Answer 1

好吧，现在可以肯定了:格式属于ftrace工具。 Android atrace 是 ftrace 构建的扩展，以方便配置。

ftrace 的官方文档表明，这种输出格式可以通过以下方式直接生成:

root@adroid:# echo 1 > /sys/kernel/debug/tracing/events/sched/sched_switch/enable
root@adroid:# echo 1 > /sys/kernel/debug/tracing/tracing_on
root@adroid:# cat /sys/kernel/debug/tracing/trace > mytracefile.txt
root@adroid:# echo 0 > /sys/kernel/debug/tracing/tracing_on
root@adroid:# echo 0 > /sys/kernel/debug/tracing/events/sched/sched_switch/enable

官方文档位于: http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/trace/ftrace.txt

# cat trace
# tracer: nop
#
# entries-in-buffer/entries-written: 77/77   #P:8
#
#                              _-----=> irqs-off
#                             / _----=> need-resched
#                            | / _---=> hardirq/softirq
#                            || / _--=> preempt-depth
#                            ||| /     delay
#           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
#              | |       |   ||||       |         |
          <idle>-0     [007] d...  2440.707395: sched_switch: prev_comm=swapper/7 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=snapshot-test-2 next_pid=2243 next_prio=120
 snapshot-test-2-2229  [002] d...  2440.707438: sched_switch: prev_comm=snapshot-test-2 prev_pid=2229 prev_prio=120 prev_state=S ==> next_comm=swapper/2 next_pid=0 next_prio=120
[...]

问候，