Parser: Report use counts once per feature

Parser: Report use counts once per feature

Reporting use counts by invoking a callback once per occurrence has
a large overhead cost in certain situations, for example when it needs
to be dispatched to a different thread (which is the case for Web Workers).

Parsing large scripts can produce a lot of occurrences (strict/sloppy mode
once per function).

Chromium (the only known user of UseCounters so far) does not actually care
about number of occurrences, but simply whether they happened at least once.
This commit changes behavior to report features at most once, which dramatically
improves performance for impacted use cases, and should not affect the only
known real world usage.

R=littledan@chromium.org
BUG=chromium:614775
Committed: https://crrev.com/2f6be682aca10c8d5c93599f8fa0e50b6359f016
Cr-Commit-Position: refs/heads/master@{#36979}

[Dan Ehrenberg, 2016-06-14 19:56:52]

Could you explain the motivation for the change in the commit message?

[Oleksandr Chekhovskyi, 2016-06-14 20:22:21]

On 2016/06/14 19:56:52, Dan Ehrenberg wrote:
> Could you explain the motivation for the change in the commit message?

I have uploaded a new (amended) commit with improved message.
I don't see it anywhere on this page though. There are side-by-side diffs per
file, but it does not seem to show commit messages anywhere.

[Dan Ehrenberg, 2016-06-14 20:25:55]

On 2016/06/14 at 20:22:21, oleksandr.chekhovskyi wrote:
> On 2016/06/14 19:56:52, Dan Ehrenberg wrote:
> > Could you explain the motivation for the change in the commit message?
> 
> I have uploaded a new (amended) commit with improved message.
> I don't see it anywhere on this page though. There are side-by-side diffs per
file, but it does not seem to show commit messages anywhere.

You have to click the "edit" link to change the commit message; the git commit
message does not get updated anywhere.

[Oleksandr Chekhovskyi, 2016-06-14 20:27:33]

Description was changed from

==========
Parser: Report use counts once per feature

R=littledan@chromium.org
BUG=chromium:614775
==========

to

==========
Parser: Report use counts once per feature

Reporting use counts by invoking a callback once per occurrence has
a large overhead cost in certain situations, for example when it needs
to be dispatched to a different thread (which is the case for Web Workers).

Parsing large scripts can produce a lot of occurrences (strict/sloppy mode
once per function).

Chromium (the only known user of UseCounters so far) does not actually care
about number of occurrences, but simply whether they happened at least once.
This commit changes behavior to report features at most once, which dramatically
improves performance for impacted use cases, and should not affect the only
known real world usage.

R=littledan@chromium.org
BUG=chromium:614775
==========

[Oleksandr Chekhovskyi, 2016-06-14 20:31:15]

On 2016/06/14 20:25:55, Dan Ehrenberg wrote:
> On 2016/06/14 at 20:22:21, oleksandr.chekhovskyi wrote:
> > On 2016/06/14 19:56:52, Dan Ehrenberg wrote:
> > > Could you explain the motivation for the change in the commit message?
> > 
> > I have uploaded a new (amended) commit with improved message.
> > I don't see it anywhere on this page though. There are side-by-side diffs
per
> file, but it does not seem to show commit messages anywhere.
> 
> You have to click the "edit" link to change the commit message; the git commit
> message does not get updated anywhere.

Description is updated now (via "Edit Issue").

[Dan Ehrenberg, 2016-06-14 20:46:23]

lgtm

Looks great, thanks!

[Dan Ehrenberg, 2016-06-14 20:46:27]

The CQ bit was checked by littledan@chromium.org

[commit-bot: I haz the power, 2016-06-14 20:46:37]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2062203002/20001

[commit-bot: I haz the power, 2016-06-14 21:39:45]

Description was changed from

==========
Parser: Report use counts once per feature

Reporting use counts by invoking a callback once per occurrence has
a large overhead cost in certain situations, for example when it needs
to be dispatched to a different thread (which is the case for Web Workers).

Parsing large scripts can produce a lot of occurrences (strict/sloppy mode
once per function).

Chromium (the only known user of UseCounters so far) does not actually care
about number of occurrences, but simply whether they happened at least once.
This commit changes behavior to report features at most once, which dramatically
improves performance for impacted use cases, and should not affect the only
known real world usage.

R=littledan@chromium.org
BUG=chromium:614775
==========

to

==========
Parser: Report use counts once per feature

Reporting use counts by invoking a callback once per occurrence has
a large overhead cost in certain situations, for example when it needs
to be dispatched to a different thread (which is the case for Web Workers).

Parsing large scripts can produce a lot of occurrences (strict/sloppy mode
once per function).

Chromium (the only known user of UseCounters so far) does not actually care
about number of occurrences, but simply whether they happened at least once.
This commit changes behavior to report features at most once, which dramatically
improves performance for impacted use cases, and should not affect the only
known real world usage.

R=littledan@chromium.org
BUG=chromium:614775
==========

[commit-bot: I haz the power, 2016-06-14 21:39:47]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-06-14 21:41:46]

Description was changed from

==========
Parser: Report use counts once per feature

Reporting use counts by invoking a callback once per occurrence has
a large overhead cost in certain situations, for example when it needs
to be dispatched to a different thread (which is the case for Web Workers).

Parsing large scripts can produce a lot of occurrences (strict/sloppy mode
once per function).

Chromium (the only known user of UseCounters so far) does not actually care
about number of occurrences, but simply whether they happened at least once.
This commit changes behavior to report features at most once, which dramatically
improves performance for impacted use cases, and should not affect the only
known real world usage.

R=littledan@chromium.org
BUG=chromium:614775
==========

to

==========
Parser: Report use counts once per feature

Reporting use counts by invoking a callback once per occurrence has
a large overhead cost in certain situations, for example when it needs
to be dispatched to a different thread (which is the case for Web Workers).

Parsing large scripts can produce a lot of occurrences (strict/sloppy mode
once per function).

Chromium (the only known user of UseCounters so far) does not actually care
about number of occurrences, but simply whether they happened at least once.
This commit changes behavior to report features at most once, which dramatically
improves performance for impacted use cases, and should not affect the only
known real world usage.

R=littledan@chromium.org
BUG=chromium:614775

Committed: https://crrev.com/2f6be682aca10c8d5c93599f8fa0e50b6359f016
Cr-Commit-Position: refs/heads/master@{#36979}
==========

[commit-bot: I haz the power, 2016-06-14 21:41:47]

Patchset 2 (id:??) landed as
https://crrev.com/2f6be682aca10c8d5c93599f8fa0e50b6359f016
Cr-Commit-Position: refs/heads/master@{#36979}