am 102ead3a: am b10e562b: Merge "Introduce a mechanism to trace boot sequence."
* commit '102ead3ae187a007b8a90b61ea243197927b6ae2':
Introduce a mechanism to trace boot sequence.
diff --git a/init/readme.txt b/init/readme.txt
index 5a758d7..d70c6f3 100644
--- a/init/readme.txt
+++ b/init/readme.txt
@@ -377,6 +377,29 @@
bootanimation ends at: 33790 31230 (-2560)
+Systrace
+--------
+Systrace [1] can be used for obtaining performance analysis reports during boot
+time on userdebug or eng builds.
+Here is an example of trace events of "wm" and "am" categories:
+
+ $ANDROID_BUILD_TOP/external/chromium-trace/systrace.py wm am --boot
+
+This command will cause the device to reboot. After the device is rebooted and
+the boot sequence has finished, the trace report is obtained from the device
+and written as trace.html on the host by hitting Ctrl+C.
+
+LIMITATION
+Recording trace events is started after persistent properties are loaded, so
+the trace events that are emitted before that are not recorded. Several
+services such as vold, surfaceflinger, and servicemanager are affected by this
+limitation since they are started before persistent properties are loaded.
+Zygote initialization and the processes that are forked from the zygote are not
+affected.
+
+[1] http://developer.android.com/tools/help/systrace.html
+
+
Debugging init
--------------
By default, programs executed by init will drop stdout and stderr into
diff --git a/rootdir/init.rc b/rootdir/init.rc
index a4a93db..16b186d 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -295,6 +295,7 @@
chmod 0660 /data/misc/wifi/wpa_supplicant.conf
mkdir /data/local 0751 root root
mkdir /data/misc/media 0700 media media
+ mkdir /data/misc/boottrace 0771 system shell
# For security reasons, /data/local/tmp should always be empty.
# Do not place files or directories in /data/local/tmp
diff --git a/rootdir/init.trace.rc b/rootdir/init.trace.rc
index 50944e6..ed4629e 100644
--- a/rootdir/init.trace.rc
+++ b/rootdir/init.trace.rc
@@ -33,3 +33,11 @@
# Allow only the shell group to read and truncate the kernel trace.
chown root shell /sys/kernel/debug/tracing/trace
chmod 0660 /sys/kernel/debug/tracing/trace
+
+on property:persist.debug.atrace.boottrace=1
+ start boottrace
+
+# Run atrace with the categories written in a file
+service boottrace /system/bin/atrace --async_start -f /data/misc/boottrace/categories
+ disabled
+ oneshot