Trace tracing Start/Stop events.

Trace tracing Start/Stop events.

Permits measuring times from start of recording (usually start of a
call), and not time from first event that occurs after tracing starts.

BUG=
R=tommi@webrtc.org

Committed: https://crrev.com/dda8a837ce51fa7fe020bfb3f017fbcdb138f875
Cr-Commit-Position: refs/heads/master@{#11815}

[pbos-webrtc, 2016-02-29 12:39:16]

PTAL, this gives better timing information since start of calls.

[pbos-webrtc, 2016-02-29 12:41:17]

The CQ bit was checked by pbos@webrtc.org to run a CQ dry run

[commit-bot: I haz the power, 2016-02-29 12:41:26]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1746693002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1746693002/1

[commit-bot: I haz the power, 2016-02-29 13:07:10]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-02-29 13:07:11]

Dry run: Try jobs failed on following builders:
  win_drmemory_light on tryserver.webrtc (JOB_FAILED,
http://build.chromium.org/p/tryserver.webrtc/builders/win_drmemory_light/buil...)

[tommi, 2016-02-29 13:12:27]

https://codereview.webrtc.org/1746693002/diff/1/webrtc/base/event_tracer.cc
File webrtc/base/event_tracer.cc (right):

https://codereview.webrtc.org/1746693002/diff/1/webrtc/base/event_tracer.cc#n...
webrtc/base/event_tracer.cc:161: TRACE_EVENT_INSTANT0("webrtc",
"EventLogger::Start");
would TRACE_EVENT_BEGIN0 and TRACE_EVENT_END0 be more appropriate?

Also, Start() and Stop() must occur on the same thread then but I don't see any
thread checks.

[pbos-webrtc, 2016-02-29 13:23:43]

PTAL

https://codereview.webrtc.org/1746693002/diff/1/webrtc/base/event_tracer.cc
File webrtc/base/event_tracer.cc (right):

https://codereview.webrtc.org/1746693002/diff/1/webrtc/base/event_tracer.cc#n...
webrtc/base/event_tracer.cc:161: TRACE_EVENT_INSTANT0("webrtc",
"EventLogger::Start");
On 2016/02/29 13:12:27, tommi-webrtc wrote:
> would TRACE_EVENT_BEGIN0 and TRACE_EVENT_END0 be more appropriate?
> 
> Also, Start() and Stop() must occur on the same thread then but I don't see
any
> thread checks.

I don't think it's particularly useful to have a begin/end event that spans the
entire tracing period (it'd just add one bar that spans the entire graph). Added
thread checks.

[pbos-webrtc, 2016-02-29 13:24:26]

add thread checks

[tommi, 2016-02-29 13:26:49]

ok, makes sense. lgtm.

[pbos-webrtc, 2016-02-29 13:54:19]

Description was changed from

==========
Trace tracing Start/Stop events.

Permits measuring times from start of recording (usually start of a
call), and not time from first event that occurs after tracing starts.

BUG=
R=tommi@webrtc.org
==========

to

==========
Trace tracing Start/Stop events.

Permits measuring times from start of recording (usually start of a
call), and not time from first event that occurs after tracing starts.

BUG=
R=tommi@webrtc.org

Committed:
https://chromium.googlesource.com/external/webrtc/+/dda8a837ce51fa7fe020bfb3f...
==========

[pbos-webrtc, 2016-02-29 13:54:20]

Committed patchset #2 (id:20001) manually as
dda8a837ce51fa7fe020bfb3f017fbcdb138f875 (presubmit successful).

[commit-bot: I haz the power, 2016-02-29 13:54:20]

Description was changed from

==========
Trace tracing Start/Stop events.

Permits measuring times from start of recording (usually start of a
call), and not time from first event that occurs after tracing starts.

BUG=
R=tommi@webrtc.org

Committed:
https://chromium.googlesource.com/external/webrtc/+/dda8a837ce51fa7fe020bfb3f...
==========

to

==========
Trace tracing Start/Stop events.

Permits measuring times from start of recording (usually start of a
call), and not time from first event that occurs after tracing starts.

BUG=
R=tommi@webrtc.org

Committed: https://crrev.com/dda8a837ce51fa7fe020bfb3f017fbcdb138f875
Cr-Commit-Position: refs/heads/master@{#11815}
==========

[commit-bot: I haz the power, 2016-02-29 13:54:21]

Patchset 2 (id:??) landed as
https://crrev.com/dda8a837ce51fa7fe020bfb3f017fbcdb138f875
Cr-Commit-Position: refs/heads/master@{#11815}