Save heap object tracking data in heap snapshot

Save heap object tracking data in heap snapshot

Every time embedder calls v8::HeapProfiler::GetHeapStats we store next unuassigned heap object id and timestamp of the request. This patch serializes all that data into heap snapshot so that embedder can restore allocation timeline.

BUG=chromium:467222
LOG=Y

Committed: https://crrev.com/aca7895353e4e4b46124a4873f8119a0a89c33a1
Cr-Commit-Position: refs/heads/master@{#27384}

[yurys, 2015-03-19 13:45:33]

yurys@chromium.org changed reviewers:
+ alph@chromium.org, loislo@chromium.org

[alph, 2015-03-19 14:05:27]

lgtm

https://codereview.chromium.org/1019813004/diff/1/src/heap-snapshot-generator.cc
File src/heap-snapshot-generator.cc (right):

https://codereview.chromium.org/1019813004/diff/1/src/heap-snapshot-generator...
src/heap-snapshot-generator.cc:3080:
base::TimeDelta().InMilliseconds())>::kUnsigned  // NOLINT
one is timedelta, another is id. these are two different types.

https://codereview.chromium.org/1019813004/diff/1/src/heap-snapshot-generator...
src/heap-snapshot-generator.cc:3088: if (first_entry) {
i != 0

https://codereview.chromium.org/1019813004/diff/1/src/heap-snapshot-generator...
src/heap-snapshot-generator.cc:3094: buffer_pos =
utoa(time_delta.InMilliseconds(), buffer, buffer_pos);
Let's use microseconds as we do in cpu profiler to be consistent. wdyt?

[yurys, 2015-03-19 14:13:27]

https://codereview.chromium.org/1019813004/diff/1/src/heap-snapshot-generator.cc
File src/heap-snapshot-generator.cc (right):

https://codereview.chromium.org/1019813004/diff/1/src/heap-snapshot-generator...
src/heap-snapshot-generator.cc:3080:
base::TimeDelta().InMilliseconds())>::kUnsigned  // NOLINT
On 2015/03/19 14:05:27, alph wrote:
> one is timedelta, another is id. these are two different types.

Done.

https://codereview.chromium.org/1019813004/diff/1/src/heap-snapshot-generator...
src/heap-snapshot-generator.cc:3088: if (first_entry) {
On 2015/03/19 14:05:27, alph wrote:
> i != 0

Done.

https://codereview.chromium.org/1019813004/diff/1/src/heap-snapshot-generator...
src/heap-snapshot-generator.cc:3094: buffer_pos =
utoa(time_delta.InMilliseconds(), buffer, buffer_pos);
On 2015/03/19 14:05:27, alph wrote:
> Let's use microseconds as we do in cpu profiler to be consistent. wdyt?

Done.

[yurys, 2015-03-19 14:14:18]

Yang: please do OWNERS review.

[yurys, 2015-03-19 16:14:41]

yurys@chromium.org changed reviewers:
+ yangguo@chromium.org

[yurys, 2015-03-19 16:14:42]

Yang: please do OWNERS review.

[alph, 2015-03-19 20:43:53]

https://codereview.chromium.org/1019813004/diff/20001/src/heap-snapshot-gener...
File src/heap-snapshot-generator.cc (right):

https://codereview.chromium.org/1019813004/diff/20001/src/heap-snapshot-gener...
src/heap-snapshot-generator.cc:2949: JSON_S("timstamp_ms") ","
_usec or just timestamp?

[yurys, 2015-03-20 08:30:41]

https://codereview.chromium.org/1019813004/diff/20001/src/heap-snapshot-gener...
File src/heap-snapshot-generator.cc (right):

https://codereview.chromium.org/1019813004/diff/20001/src/heap-snapshot-gener...
src/heap-snapshot-generator.cc:2949: JSON_S("timstamp_ms") ","
On 2015/03/19 20:43:53, alph wrote:
> _usec or just timestamp?

Done.

[Yang, 2015-03-20 10:24:59]

On 2015/03/20 08:30:41, yurys wrote:
>
https://codereview.chromium.org/1019813004/diff/20001/src/heap-snapshot-gener...
> File src/heap-snapshot-generator.cc (right):
> 
>
https://codereview.chromium.org/1019813004/diff/20001/src/heap-snapshot-gener...
> src/heap-snapshot-generator.cc:2949: JSON_S("timstamp_ms") ","
> On 2015/03/19 20:43:53, alph wrote:
> > _usec or just timestamp?
> 
> Done.

Can we have a test case or extend an existing one?

[yurys, 2015-03-20 10:38:13]

On 2015/03/20 10:24:59, Yang wrote:
> On 2015/03/20 08:30:41, yurys wrote:
> >
>
https://codereview.chromium.org/1019813004/diff/20001/src/heap-snapshot-gener...
> > File src/heap-snapshot-generator.cc (right):
> > 
> >
>
https://codereview.chromium.org/1019813004/diff/20001/src/heap-snapshot-gener...
> > src/heap-snapshot-generator.cc:2949: JSON_S("timstamp_ms") ","
> > On 2015/03/19 20:43:53, alph wrote:
> > > _usec or just timestamp?
> > 
> > Done.
> 
> Can we have a test case or extend an existing one?

Historically all tests of the serialized snapshot live in Blink, on v8 side we
only have tests for heap data collection using v8-profiler.h
API(test-heap-profiler.cc). I'm going to add new tests for this functionality in
Blink.

[Yang, 2015-03-20 10:40:31]

On 2015/03/20 10:38:13, yurys wrote:
> On 2015/03/20 10:24:59, Yang wrote:
> > On 2015/03/20 08:30:41, yurys wrote:
> > >
> >
>
https://codereview.chromium.org/1019813004/diff/20001/src/heap-snapshot-gener...
> > > File src/heap-snapshot-generator.cc (right):
> > > 
> > >
> >
>
https://codereview.chromium.org/1019813004/diff/20001/src/heap-snapshot-gener...
> > > src/heap-snapshot-generator.cc:2949: JSON_S("timstamp_ms") ","
> > > On 2015/03/19 20:43:53, alph wrote:
> > > > _usec or just timestamp?
> > > 
> > > Done.
> > 
> > Can we have a test case or extend an existing one?
> 
> Historically all tests of the serialized snapshot live in Blink, on v8 side we
> only have tests for heap data collection using v8-profiler.h
> API(test-heap-profiler.cc). I'm going to add new tests for this functionality
in
> Blink.

lgtm.

[yurys, 2015-03-24 04:59:18]

The CQ bit was checked by yurys@chromium.org

[yurys, 2015-03-24 04:59:19]

The patchset sent to the CQ was uploaded after l-g-t-m from alph@chromium.org,
yangguo@chromium.org
Link to the patchset: https://codereview.chromium.org/1019813004/#ps80001
(title: " ")

[commit-bot: I haz the power, 2015-03-24 04:59:28]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1019813004/80001

[commit-bot: I haz the power, 2015-03-24 05:50:02]

Committed patchset #5 (id:80001)

[commit-bot: I haz the power, 2015-03-24 05:50:11]

Patchset 5 (id:??) landed as
https://crrev.com/aca7895353e4e4b46124a4873f8119a0a89c33a1
Cr-Commit-Position: refs/heads/master@{#27384}