[inspector] removed kDebugPromiseCollected event

[inspector] removed kDebugPromiseCollected event

With recent CLs we always store maximum N async stack traces and when we reach limit we drop half of them.
Current promise collected event requires creating weak handle:
- it takes time,
- it consumes memory.
Since async task id distribution for promises is uniform (each new promise has last_async_task_id + 1 as an id) our hash map is good enough to handle any amount of async task ids, following time of executing 1 000 000 000 of lookups:
- for empty hash map: 1.45 seconds,
- for hash map with one entry: 14.95 seconds
- 1024 entries: 15.03 seconds
- 1024 * 1024 entries: 14.82 seconds
- 1024 * 1024 * 1024: 17.9 seconds

BUG=v8:6189
R=dgozman@chromium.org,yangguo@chromium.org

Review-Url: https://codereview.chromium.org/2819423005
Cr-Commit-Position: refs/heads/master@{#44750}
Committed: https://chromium.googlesource.com/v8/v8/+/189ffd9460e27638374f35c825036ee623107f38

[kozy, 2017-04-18 17:11:54]

Dmitry and Yang, please take a look.

Removing has only one disadvantage:
if at any time in future we will decide to be better in collecting old tasks
(remove corresponded stack from global list when async task cancelled), we would
need to implement something for promise collected event.

But since we're going to increase async task limit at least in 8 times - it
should be fine as is.

[kozy, 2017-04-18 17:12:36]

The CQ bit was checked by kozyatinskiy@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-04-18 17:12:40]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-04-18 17:39:37]

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

[commit-bot: I haz the power, 2017-04-18 17:39:38]

Dry run: This issue passed the CQ dry run.

[Yang, 2017-04-18 18:30:22]

lgtm

[dgozman, 2017-04-19 20:16:36]

Let's add a test which does a lot of promises with small limit and then checks
the sizes of our internal maps to prevent future regressions.

[dgozman, 2017-04-19 20:16:49]

otherwise lgtm

[kozy, 2017-04-20 00:55:16]

The CQ bit was checked by kozyatinskiy@chromium.org

[kozy, 2017-04-20 00:55:17]

The patchset sent to the CQ was uploaded after l-g-t-m from
dgozman@chromium.org, yangguo@chromium.org
Link to the patchset: https://codereview.chromium.org/2819423005/#ps20001
(title: "added a test")

[commit-bot: I haz the power, 2017-04-20 00:55:27]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[kozy, 2017-04-20 01:18:13]

The CQ bit was unchecked by kozyatinskiy@chromium.org

[kozy, 2017-04-20 15:20:03]

The CQ bit was checked by kozyatinskiy@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-04-20 15:20:14]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-04-20 15:42:55]

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

[commit-bot: I haz the power, 2017-04-20 15:42:56]

Dry run: This issue passed the CQ dry run.

[kozy, 2017-04-20 15:47:17]

The CQ bit was checked by kozyatinskiy@chromium.org

[commit-bot: I haz the power, 2017-04-20 15:47:25]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-04-20 15:49:03]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1492703237406310,
"parent_rev": "24782a47c07455e39abb81ba04d72670bbc12f9c", "commit_rev":
"189ffd9460e27638374f35c825036ee623107f38"}

[commit-bot: I haz the power, 2017-04-20 15:49:09]

Description was changed from

==========
[inspector] removed kDebugPromiseCollected event

With recent CLs we always store maximum N async stack traces and when we reach
limit we drop half of them.
Current promise collected event requires creating weak handle:
- it takes time,
- it consumes memory.
Since async task id distribution for promises is uniform (each new promise has
last_async_task_id + 1 as an id) our hash map is good enough to handle any
amount of async task ids, following time of executing 1 000 000 000 of lookups:
- for empty hash map: 1.45 seconds,
- for hash map with one entry: 14.95 seconds
- 1024 entries: 15.03 seconds
- 1024 * 1024 entries: 14.82 seconds
- 1024 * 1024 * 1024: 17.9 seconds

BUG=v8:6189
R=dgozman@chromium.org,yangguo@chromium.org
==========

to

==========
[inspector] removed kDebugPromiseCollected event

With recent CLs we always store maximum N async stack traces and when we reach
limit we drop half of them.
Current promise collected event requires creating weak handle:
- it takes time,
- it consumes memory.
Since async task id distribution for promises is uniform (each new promise has
last_async_task_id + 1 as an id) our hash map is good enough to handle any
amount of async task ids, following time of executing 1 000 000 000 of lookups:
- for empty hash map: 1.45 seconds,
- for hash map with one entry: 14.95 seconds
- 1024 entries: 15.03 seconds
- 1024 * 1024 entries: 14.82 seconds
- 1024 * 1024 * 1024: 17.9 seconds

BUG=v8:6189
R=dgozman@chromium.org,yangguo@chromium.org

Review-Url: https://codereview.chromium.org/2819423005
Cr-Commit-Position: refs/heads/master@{#44750}
Committed:
https://chromium.googlesource.com/v8/v8/+/189ffd9460e27638374f35c825036ee6231...
==========

[commit-bot: I haz the power, 2017-04-20 15:49:10]

Committed patchset #2 (id:20001) as
https://chromium.googlesource.com/v8/v8/+/189ffd9460e27638374f35c825036ee6231...