diff options
| author | Yabin Cui <yabinc@google.com> | 2022-01-26 13:48:29 -0800 |
|---|---|---|
| committer | Yabin Cui <yabinc@google.com> | 2022-01-27 12:55:07 -0800 |
| commit | cd91e46c3f07a7739623bf3d967ae57540b2a43b (patch) | |
| tree | b419cdfb0c5d95896e1185c359cd6e57aa58d272 | |
| parent | 8f71c9629dd12044a147eb76ff12fe3be5819376 (diff) | |
| download | extras-cd91e46c3f07a7739623bf3d967ae57540b2a43b.tar.gz | |
simpleperf: add doc for getting boot-time profile.
Bug: 214731005
Test: none
Change-Id: If446962e3b32e14be96dd41ea9a926b0634c2fde
| -rw-r--r-- | simpleperf/doc/android_platform_profiling.md | 32 | ||||
| -rw-r--r-- | simpleperf/doc/pictures/boot_time_profile.png | bin | 0 -> 90649 bytes |
2 files changed, 32 insertions, 0 deletions
diff --git a/simpleperf/doc/android_platform_profiling.md b/simpleperf/doc/android_platform_profiling.md index f4899e45..f2a31cf0 100644 --- a/simpleperf/doc/android_platform_profiling.md +++ b/simpleperf/doc/android_platform_profiling.md @@ -75,3 +75,35 @@ On Pixel devices, the number of PMU counters on each core is usually 7, of which by the kernel to monitor memory latency. So only 3 counters are available. It's fine to monitor up to 3 PMU events at the same time. To monitor more than 3 events, the `--use-devfreq-counters` option can be used to borrow from the counters used by the kernel. + +## Get boot-time profile + +On userdebug/eng devices, we can get boot-time profile via simpleperf. + +Step 1. In adb root, set options used to record boot-time profile. Simpleperf stores the options in +a persist property `persist.simpleperf.boot_record`. + +``` +# simpleperf boot-record --enable "-a -g --duration 10 --exclude-perf" +``` + +Step 2. Reboot the device. When booting, init finds that the persist property is set, so it forks +a background process to run simpleperf to record boot-time profile. init starts simpleperf at +zygote-start stage, right after zygote is started. + +``` +$ adb reboot +``` + +Step 3. After boot, the boot-time profile is stored in /data/simpleperf_boot_data. Then we can pull +the profile to host to report. + +``` +$ adb shell ls /data/simpleperf_boot_data +perf-20220126-11-47-51.data +``` + +Following is a boot-time profile example. From timestamp, the first sample is generated at about +4.5s after booting. + + diff --git a/simpleperf/doc/pictures/boot_time_profile.png b/simpleperf/doc/pictures/boot_time_profile.png Binary files differnew file mode 100644 index 00000000..3e061557 --- /dev/null +++ b/simpleperf/doc/pictures/boot_time_profile.png |
