Merge "Update NDK prebuilts to build 3498956." into ndk-r14-release
diff --git a/README.md b/README.md
index 3acd33a..96f601b 100644
--- a/README.md
+++ b/README.md
@@ -178,8 +178,6 @@
# Print stat for process 11904 every 300ms.
$simpleperf stat -p 11904 --duration 10 --interval 300
- # Stop by using Ctrl-C.
- ^C
# Print system wide stat at interval of 300ms for 10 seconds (rooted device only).
# system wide profiling needs root privilege
@@ -378,9 +376,10 @@
sudo-game-jni.so. We focus on sudo-game-jni.so, not the java code or system
libraries.
-## 1. Run debug version of the app on device
-We need to run debug version of the app, because we can’t use *run-as* for non
-debuggable apps.
+## 1. Run a debuggable="true" version of the app on device
+We need to run a copy of the app with android:debuggable=”true” in its
+AndroidManfest.xml <application> element, because we can’t use run-as for
+non-debuggable apps.
## 2. Download simpleperf to the app’s directory
Use *uname* to find the architecture on device
@@ -632,6 +631,40 @@
$adb shell run-as com.example.sudogame ./simpleperf report -n -g --symfs . >perf.report
$python report.py perf.report
+## 8. Report perf.data on host
+We can also use adb to pull perf.data on host. Then use simpleperf on host to
+report it (Simpleperf on host is not provided, but can be built from source
+code). Because we don’t have any symbol information on host, we need to
+collect symbol information in perf.data while recording.
+
+ # Collect symbol information while recording.
+ device#./simpleperf record -t 25636 --dump-symbols --duration 30
+
+ # pull perf.data on host
+ host$adb shell run-as com.example.sudogame cat perf.data >perf.data
+
+ # report perf.data
+ host$simpleperf report
+
+### Show flamegraph
+Simpleperf supports reading perf.data through libsimpleperf_report.so.
+Currently, libsimpleperf_report.so is only provided on linux x86_64 platform,
+but it can be built for other platforms from source code. It has a python
+interface simpleperf_report_lib.py. So we can write python scripts to read
+perf.data. The shared library and scripts are in
+https://android.googlesource.com/platform/system/extras/+/master/simpleperf/scripts/.
+
+One example is report_sample.py. It can be used to output file used to show
+flame graph as below.
+
+ # Convert perf.data into out.perf.
+ host$python report_sample.py >out.perf
+
+ # show out.perf using flamegraph
+ host$stackcollapse-perf.pl out.perf >out.folded
+ host$./flamegraph.pl out.folded >a.svg
+
+
# Steps to profile java code on rooted devices
Simpleperf only supports profiling native instructions in binaries in ELF
format. If the java code is executed by interpreter, or with jit cache, it
