From cf6a3b915c2984ae573b27a46dd732811d642427 Mon Sep 17 00:00:00 2001
From: Jeff Hao
Date: Tue, 5 May 2015 18:36:42 -0700
Subject: Update ddms and profiling docs to include sample profiling.
Bug: 5866094
Change-Id: Ib97990ee2fc823416b3f41856b815d4092818f98
---
docs/html/tools/debugging/ddms.jd | 4 ++++
docs/html/tools/debugging/debugging-tracing.jd | 11 +++++++++--
2 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/docs/html/tools/debugging/ddms.jd b/docs/html/tools/debugging/ddms.jd
index 1b59875..5822e27 100644
--- a/docs/html/tools/debugging/ddms.jd
+++ b/docs/html/tools/debugging/ddms.jd
@@ -204,6 +204,10 @@ parent.link=index.html
Click the Start Method Profiling button.
+ In Android 4.4 and later, choose either trace-based profiling or sample-based profiling
+ with a specified sampling interval. For earlier versions of Android, only trace-based profiling
+ is available.
+
Interact with your application to start the methods that you want to profile.
Click the Stop Method Profiling button. DDMS stops profiling your
diff --git a/docs/html/tools/debugging/debugging-tracing.jd b/docs/html/tools/debugging/debugging-tracing.jd
index bd4afbc..098660b 100644
--- a/docs/html/tools/debugging/debugging-tracing.jd
+++ b/docs/html/tools/debugging/debugging-tracing.jd
@@ -127,7 +127,7 @@ parent.link=index.html
{@link android.os.Debug#startMethodTracing() startMethodTracing()} methods. In the call, you
specify a base name for the trace files that the system generates. To stop tracing, call {@link
android.os.Debug#stopMethodTracing() stopMethodTracing()}. These methods start and stop method
- tracing across the entire virtual machine. For example, you could call
+ tracing across the entire virtual machine. For example, you could call
{@link android.os.Debug#startMethodTracing() startMethodTracing()} in
your activity's {@link android.app.Activity#onCreate onCreate()} method, and call
{@link android.os.Debug#stopMethodTracing() stopMethodTracing()} in that activity's
@@ -157,6 +157,12 @@ parent.link=index.html
times are only useful in relation to other profile output, so you can see if changes have made
the code faster or slower relative to a previous profiling run.
+ In Android 4.4 and later, you can use sample-based profiling to profile with less runtime
+ performance impact. To enable sample profiling, call {@link
+ android.os.Debug#startMethodTracingSampling() startMethodTracingSampling()} with a specified
+ sampling interval. The system will then gather samples periodically until tracing is stopped
+ via {@link android.os.Debug#stopMethodTracing() stopMethodTracing()}.
+
Copying Trace Files to a Host Machine
After your application has run and the system has created your trace files
@@ -277,7 +283,8 @@ dmtracedump [-ho] [-s sortable] [-d trace-base-name] [-g outfile] <trace-base
Traceview logging does not handle threads well, resulting in these two problems:
- - If a thread exits during profiling, the thread name is not emitted;
+ - If a thread exits during profiling, the thread name is not emitted (fixed in Android 5.1
+ and later);
- The VM reuses thread IDs. If a thread stops and another starts, they may get the same
ID.
--
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