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Issue 883398 link

Starred by 1 user

Issue metadata

Status: Verified
Owner:
Closed: Sep 19
Cc:
Components:
EstimatedDays: ----
NextAction: ----
OS: Windows
Pri: 1
Type: Bug-Regression



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38.0ms render process startup (and jank) regression in SpellCheck::Initialize()

Project Member Reported by wittman@chromium.org, Sep 12

Issue description

Data from the UMA Sampling Profiler shows that SpellCheck::Initialize() runtime regressed during renderer process main thread startup on 64-bit Chrome on Windows by 38.0ms on average. This occurred in the 70.0.3532.2 Canary release.

The regression is non-uniform across the userbase and is resulting in significant jank: 700ms at the 99th %ile and 2.5s at the 99.9th %ile. See attached SpellCheckJank.png for more detail.

Suspected CL:
Fix first word spellcheck.
ganenkokb@yandex-team.ru
e7f35a93db7e02a177ee4e768dd8c66e3043d7c4

Execution profile difference of Canary 70.0.3530.0 vs. 70.0.3532.2: https://uma.googleplex.com/p/chrome/callstacks?sid=33ed3ad7c755c5a8cdafbba95cc60a26 (Google-internal link; see attached SpellCheckProfile.png for the same profile information.)

Assigning to groby@ who reviewed the original CL.


 
SpellCheckJank.png
54.7 KB View Download
SpellCheckProfile.png
188 KB View Download
Cc: yyushkina@chromium.org
I don't see an easy way to address this - in that context, I'd recommend a rollback for the CL, unless ganenkob@ has a better solution?

+yyushkina FYI
Seems like we should go ahead and revert the original CL, and try to merge the revert into M70. groby, do you want to do the honors?
I'm currently somewhat drowning in administrivia. Happy to rubberstamp a revert, but can't get to it myself soon-ish. Would you mind?
Cc: groby@chromium.org
Owner: wittman@chromium.org
Sure, I'll push it through.
Project Member

Comment 6 by bugdroid1@chromium.org, Sep 17

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5fe8de1abd4bd5a1d87d5e7e801b3949adf35230

commit 5fe8de1abd4bd5a1d87d5e7e801b3949adf35230
Author: Mike Wittman <wittman@chromium.org>
Date: Mon Sep 17 21:26:02 2018

Revert "Fix first word spellcheck."

This reverts commit e7f35a93db7e02a177ee4e768dd8c66e3043d7c4.

Reason for revert: Causes significant startup and jank regressions.

Original change's description:
> Fix first word spellcheck.
> 
> Do not process pending request if initialize call is come with not inited
>  dictionaries.
> 
> R=​groby@chromium.org
> 
> Bug: 850424
> Change-Id: I0dd7213f9865b2c5949fd6367c524edfd09febf1
> Reviewed-on: https://chromium-review.googlesource.com/1085449
> Commit-Queue: Rachel Blum <groby@chromium.org>
> Reviewed-by: Rachel Blum <groby@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#585283}

TBR=groby@chromium.org,ganenkokb@yandex-team.ru

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 850424,  883398 
Change-Id: If2b242b87a44d40010427a3e0a6474c103f8f054
Reviewed-on: https://chromium-review.googlesource.com/1228934
Reviewed-by: Mike Wittman <wittman@chromium.org>
Reviewed-by: Rachel Blum <groby@chromium.org>
Commit-Queue: Mike Wittman <wittman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#591821}
[modify] https://crrev.com/5fe8de1abd4bd5a1d87d5e7e801b3949adf35230/components/spellcheck/renderer/spellcheck.cc
[modify] https://crrev.com/5fe8de1abd4bd5a1d87d5e7e801b3949adf35230/components/spellcheck/renderer/spellcheck_unittest.cc

Status: Verified (was: Assigned)
The regression is fixed per https://uma.googleplex.com/p/chrome/callstacks?sid=679f1fa87387473450a4586b312f1ae1. We see a 39.4ms average decrease in time spent by SpellCheck::Initialize().
Labels: Merge-Request-70
Requesting merge for M70: this fixes a major renderer process startup regression. This fix is a clean revert to the behavior prior to 70.0.3532.0 and has been in canary for two days.
Project Member

Comment 9 by sheriffbot@chromium.org, Sep 19

Labels: -Merge-Request-70 Merge-Review-70 Hotlist-Merge-Review
This bug requires manual review: Reverts referenced in bugdroid comments after merge request.
Please contact the milestone owner if you have questions.
Owners: benmason@(Android), kariahda@(iOS), geohsu@(ChromeOS), abdulsyed@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot
Cc: chengx@chromium.org
Ping for manual review as in comment #9.
Labels: -Merge-Review-70 Merge-Approved-70
Project Member

Comment 13 by bugdroid1@chromium.org, Sep 20

Labels: -merge-approved-70 merge-merged-3538
The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/6acaa334121b4607e9417eaaff7141bd90e520dc

commit 6acaa334121b4607e9417eaaff7141bd90e520dc
Author: Mike Wittman <wittman@chromium.org>
Date: Thu Sep 20 20:58:52 2018

Revert "Fix first word spellcheck."

This reverts commit e7f35a93db7e02a177ee4e768dd8c66e3043d7c4.

Reason for revert: Causes significant startup and jank regressions.

Original change's description:
> Fix first word spellcheck.
> 
> Do not process pending request if initialize call is come with not inited
>  dictionaries.
> 
> R=​groby@chromium.org
> 
> Bug: 850424
> Change-Id: I0dd7213f9865b2c5949fd6367c524edfd09febf1
> Reviewed-on: https://chromium-review.googlesource.com/1085449
> Commit-Queue: Rachel Blum <groby@chromium.org>
> Reviewed-by: Rachel Blum <groby@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#585283}

TBR=groby@chromium.org,ganenkokb@yandex-team.ru

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 850424,  883398 
Change-Id: If2b242b87a44d40010427a3e0a6474c103f8f054
Reviewed-on: https://chromium-review.googlesource.com/1228934
Reviewed-by: Mike Wittman <wittman@chromium.org>
Reviewed-by: Rachel Blum <groby@chromium.org>
Commit-Queue: Mike Wittman <wittman@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#591821}(cherry picked from commit 5fe8de1abd4bd5a1d87d5e7e801b3949adf35230)
Reviewed-on: https://chromium-review.googlesource.com/1237261
Reviewed-by: Xi Cheng <chengx@chromium.org>
Cr-Commit-Position: refs/branch-heads/3538@{#551}
Cr-Branched-From: 79f7c91a2b2a2932cd447fa6f865cb6662fa8fa6-refs/heads/master@{#587811}
[modify] https://crrev.com/6acaa334121b4607e9417eaaff7141bd90e520dc/components/spellcheck/renderer/spellcheck.cc
[modify] https://crrev.com/6acaa334121b4607e9417eaaff7141bd90e520dc/components/spellcheck/renderer/spellcheck_unittest.cc

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