[Fuchsia] Routes timeline events to Fuchsia's tracing app

[Fuchsia] Routes timeline events to Fuchsia's tracing app

This CL routes timeline events to Fuchsia's tracing app when the
following arguments are passed to the VM:

--systrace_timeline
--timeline_recorder=systrace
--timeline_streams=[some streams here]

I'll add these arguments to the Flutter engine for Fuchsia after this
CL lands.

TO-367

R=rmacnak@google.com

Committed: https://github.com/dart-lang/sdk/commit/b3200f4664b0d6da726f4544a591213997869cf7

[zra, 2017-07-10 20:22:05]

Description was changed from

==========
[Fuchsia] Routes timeline events to Fuchsia's tracing app
==========

to

==========
[Fuchsia] Routes timeline events to Fuchsia's tracing app

This CL routes timeline events to Fuchsia's tracing app when the
following arguments are passed to the VM:

--systrace_timeline
--timeline_recorder=systrace
--timeline_streams=[some streams here]

I'll add these arguments to the Flutter engine for Fuchsia after this
CL lands.
==========

[zra, 2017-07-10 20:23:00]

Description was changed from

==========
[Fuchsia] Routes timeline events to Fuchsia's tracing app

This CL routes timeline events to Fuchsia's tracing app when the
following arguments are passed to the VM:

--systrace_timeline
--timeline_recorder=systrace
--timeline_streams=[some streams here]

I'll add these arguments to the Flutter engine for Fuchsia after this
CL lands.
==========

to

==========
[Fuchsia] Routes timeline events to Fuchsia's tracing app

This CL routes timeline events to Fuchsia's tracing app when the
following arguments are passed to the VM:

--systrace_timeline
--timeline_recorder=systrace
--timeline_streams=[some streams here]

I'll add these arguments to the Flutter engine for Fuchsia after this
CL lands.

TO-367
==========

[zra, 2017-07-10 20:23:56]

zra@google.com changed reviewers:
+ rmacnak@google.com

[konkers, 2017-07-10 20:42:08]

Systrace is Android specific term.  Perhaps it would be better to decouple the
two and make TimelineEventFuchsiaRecorder.

[rmacnak, 2017-07-10 23:38:48]

On 2017/07/10 20:42:08, konkers wrote:
> Systrace is Android specific term.  Perhaps it would be better to decouple the
> two and make TimelineEventFuchsiaRecorder.

I think it makes sense have a single flag for "record to the underlying
platform's tracing service".

[rmacnak, 2017-07-10 23:39:02]

https://codereview.chromium.org/2977513002/diff/20001/runtime/vm/timeline.cc
File runtime/vm/timeline.cc (right):

https://codereview.chromium.org/2977513002/diff/20001/runtime/vm/timeline.cc#...
runtime/vm/timeline.cc:422: Init(kDuration, label);
Maybe emit a Fuchsia tracing duration start here instead of the
DurationEventScope.

https://codereview.chromium.org/2977513002/diff/20001/runtime/vm/timeline.cc#...
runtime/vm/timeline.cc:607: // TODO(zra): Figure out what to do with kDuration,
kCounter, and
Duration is the most common event type.

[zra, 2017-07-11 17:38:04]

I've split the Fuchsia specific stuff into TimelineEventFuchsiaRecorder.
Arguably, Linux and Android should be disentangled as well, especially if we'll
want MacOS and Windows "systrace" recorders at some point, and they should be
refactored to go in timeline_{android,linux,...}.cc files, but we should wait to
cross that bridge until we come to it.

The command line flags will probably have to continue to include "systrace"
unless it's worth a breaking change to do a rename.

https://codereview.chromium.org/2977513002/diff/20001/runtime/vm/timeline.cc
File runtime/vm/timeline.cc (right):

https://codereview.chromium.org/2977513002/diff/20001/runtime/vm/timeline.cc#...
runtime/vm/timeline.cc:422: Init(kDuration, label);
On 2017/07/10 23:39:01, rmacnak wrote:
> Maybe emit a Fuchsia tracing duration start here instead of the
> DurationEventScope.

event->Duration() and event->Complete() are both called from
TimelineDurationScope::~TimelineDurationScope(), which would give the wrong
result. They are also both called from Dart_TimelineEvent().

https://codereview.chromium.org/2977513002/diff/20001/runtime/vm/timeline.cc#...
runtime/vm/timeline.cc:607: // TODO(zra): Figure out what to do with kDuration,
kCounter, and
On 2017/07/10 23:39:02, rmacnak wrote:
> Duration is the most common event type.

Except when coming through Dart_TimelineEvent(), kDuration only comes through
TimelineDurationScopes. Flutter engine already routes around
Dart_TimelineEvent() in Fuchsia, and dart:developer Timeline doesn't appear to
generate Duration events, so I think we probably won't even see kDuration here.

[rmacnak, 2017-07-11 20:04:47]

LGTM

The current systrace flag is only used manually, so feel free to rename it.

https://codereview.chromium.org/2977513002/diff/40001/runtime/vm/timeline.h
File runtime/vm/timeline.h (right):

https://codereview.chromium.org/2977513002/diff/40001/runtime/vm/timeline.h#n...
runtime/vm/timeline.h:752: class TimelineEventFuchsiaRecorder : public
TimelineEventFixedBufferRecorder {
Reference https://fuchsia.googlesource.com/tracing/+/HEAD/docs/usage_guide.md

[zra, 2017-07-11 20:39:59]

I've left the flag named --systrace_timeline but updated the help text to be
more generic.

https://codereview.chromium.org/2977513002/diff/40001/runtime/vm/timeline.h
File runtime/vm/timeline.h (right):

https://codereview.chromium.org/2977513002/diff/40001/runtime/vm/timeline.h#n...
runtime/vm/timeline.h:752: class TimelineEventFuchsiaRecorder : public
TimelineEventFixedBufferRecorder {
On 2017/07/11 20:04:47, rmacnak wrote:
> Reference https://fuchsia.googlesource.com/tracing/+/HEAD/docs/usage_guide.md

Done.

[zra, 2017-07-11 21:12:33]

Description was changed from

==========
[Fuchsia] Routes timeline events to Fuchsia's tracing app

This CL routes timeline events to Fuchsia's tracing app when the
following arguments are passed to the VM:

--systrace_timeline
--timeline_recorder=systrace
--timeline_streams=[some streams here]

I'll add these arguments to the Flutter engine for Fuchsia after this
CL lands.

TO-367
==========

to

==========
[Fuchsia] Routes timeline events to Fuchsia's tracing app

This CL routes timeline events to Fuchsia's tracing app when the
following arguments are passed to the VM:

--systrace_timeline
--timeline_recorder=systrace
--timeline_streams=[some streams here]

I'll add these arguments to the Flutter engine for Fuchsia after this
CL lands.

TO-367

R=rmacnak@google.com

Committed:
https://github.com/dart-lang/sdk/commit/b3200f4664b0d6da726f4544a591213997869cf7
==========

[zra, 2017-07-11 21:12:34]

Committed patchset #5 (id:80001) manually as
b3200f4664b0d6da726f4544a591213997869cf7 (presubmit successful).