Add --trace-memory option for tracing heap memory

build/android/adb_profile_chrome.py

Index: build/android/adb_profile_chrome.py
diff --git a/build/android/adb_profile_chrome.py b/build/android/adb_profile_chrome.py
index 2e25d9c40779229b1e7e0db57168981e0c4dd2b7..fdbed3b69ff5027880f1b77f019068f9cebaf3c7 100755
--- a/build/android/adb_profile_chrome.py
+++ b/build/android/adb_profile_chrome.py
@@ -31,7 +31,7 @@ sys.path.append(_TRACE_VIEWER_ROOT)
 from trace_viewer.build import trace2html # pylint: disable=F0401
 
 _DEFAULT_CHROME_CATEGORIES = '_DEFAULT_CHROME_CATEGORIES'
-
+_HEAP_PROFILE_MMAP = 'heapprof.mmap'

[Sami, 2014/05/19 16:00:10]

nit: could you call this _HEAP_PROFILE_MMAP_PROPERTY instead so it's a little
clearer what it is for?

[JungJik, 2014/05/19 16:35:36]

sure!

 
 def _GetTraceTimestamp():
   return time.strftime('%Y-%m-%d-%H%M%S', time.localtime())
@@ -309,6 +309,8 @@ def _ComputeChromeCategories(options):
     categories.append('disabled-by-default-gpu.debug*')
   if options.trace_flow:
     categories.append('disabled-by-default-toplevel.flow')
+  if options.trace_memory:
+    categories.append('disabled-by-default-memory')
   if options.chrome_categories:
     categories += options.chrome_categories.split(',')
   return categories
@@ -371,6 +373,9 @@ def main():
                         'GPU data.', action='store_true')
   categories.add_option('--trace-flow', help='Enable extra trace categories '
                         'for IPC message flows.', action='store_true')
+  categories.add_option('--trace-memory', help='Enable extra trace categories '
+                        'for memory profile. (tcmalloc required)',
+                        action='store_true')
   parser.add_option_group(categories)
 
   output_options = optparse.OptionGroup(parser, 'Output options')
@@ -435,6 +440,14 @@ When in doubt, just try out --trace-frame-viewer.
     _PrintMessage('Time interval or continuous tracing should be specified.')
     return 1
 
+  system_properties = device.old_interface.system_properties
+  if options.trace_memory:
+    if not device.old_interface.IsRootEnabled():
+      device.old_interface.EnableAdbRoot()

[Sami, 2014/05/19 16:00:10]

You can just call EnableAdbRoot() unconditionally since it is a no-op if we're
already root.

[JungJik, 2014/05/19 16:35:36]

thanks for your comment.

+    system_properties[_HEAP_PROFILE_MMAP] = 1
+  else:
+    system_properties[_HEAP_PROFILE_MMAP] = 0

[Sami, 2014/05/19 11:39:49]

Should we reset this property after tracing? Are there any side effects if it is
left enabled?

If so, would it make sense to add a MemoryTracingController class (similar to
ChromeTracingController etc.) that ensure the property is enabled only for the
duration of tracing?

[JungJik, 2014/05/19 12:08:10]

Thanks for your comment. 
I've just checked the code. if the profiler is stopped, the hooking functions
are unset. so whether the flag is enabled or not, it does not effect on browser.
ref: heap-profiler.cc/void HeapProfilerStop() http://goo.gl/8OC4mx

[Sami, 2014/05/19 16:00:10]

Thanks for checking. I was thinking more about the case where you record a trace
with adb_profile_chrome with --trace-memory and then use some other profiler
like telemetry. If we don't reset the flag you might get distorted results in
the second run.

[JungJik, 2014/05/19 16:35:36]

how about reset after pulling the trace file, then we don't need to worry about
the second run. I will file new patch.

+
   chrome_categories = _ComputeChromeCategories(options)
   systrace_categories = _ComputeSystraceCategories(options)