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Issue metadata

Status: WontFix
Owner:
Closed: Mar 2016
Cc:
EstimatedDays: ----
NextAction: ----
OS: ----
Pri: 2
Type: Bug-Regression



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4.1%-9.5% regression in page_cycler.tough_layout_cases at 379578:379607

Project Member Reported by qyears...@chromium.org, Mar 8 2016

Issue description

See the link to graphs below.
 
Cc: e...@chromium.org
Owner: e...@chromium.org

=== Auto-CCing suspected CL author eae@chromium.org ===

Hi eae@chromium.org, the bisect results pointed to your CL below as possibly
causing a regression. Please have a look at this info and see whether
your CL be related.


===== BISECT JOB RESULTS =====
Status: completed


===== SUSPECTED CL(s) =====
Subject : Pass Windows font rendering preferences from browser to blink
Author  : eae
Commit description:
  
Change the way Blink queries Windows font settings to work reliably with
the sandbox. Instead of calling SystemParametersInfo directly from Blink
in FontPlatformDataWin do so in the browser process and pass the desired
flags to Blink using the WebFontRendering interface. Also, use the value
should_antialias_text in Chrome's RendererPreferences object rather than
checking the SPI_GETFONTSMOOTHINGTYPE Windows system parameter directly.

Similarly use the subpixel_rendering field in RendererPreferences rather
than checking FE_FONTSMOOTHINGCLEARTYPE to control use of subpixel text.

In addition to ensure that these values are queried correctly this helps
guarantee that Chrome and Blink use the same setting for text rendering.

TBR=jam@chromium.org
BUG= 419003 

Review URL: https://codereview.chromium.org/1763803002

Cr-Commit-Position: refs/heads/master@{#379589}
Commit  : e3fe85330f1fbad6cb02cd0c5ceb09498e50f349
Date    : Mon Mar 07 18:22:20 2016


===== TESTED REVISIONS =====
Revision                Mean Value  Std. Dev.   Num Values  Good?
chromium@379577         734.593875  8.080694    5           good
chromium@379585         735.705     8.187963    5           good
chromium@379587         735.969563  5.497814    5           good
chromium@379588         734.888313  11.328744   5           good
chromium@379589         808.154188  0.910886    5           bad
chromium@379593         802.402938  1.642786    5           bad
chromium@379607         804.360563  2.585986    5           bad

Bisect job ran on: win_8_perf_bisect
Bug ID: 593102

Test Command: python src/tools/perf/run_benchmark -v --browser=release --output-format=chartjson --also-run-disabled-tests page_cycler.intl_ar_fa_he
Test Metric: warm_times/page_load_time
Relative Change: 9.50%
Score: 99.9

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/win_8_perf_bisect/builds/1871
Job details: https://chromeperf.appspot.com/buildbucket_job_status/9018730612700624720


| O O | Visit http://www.chromium.org/developers/speed-infra/perf-bug-faq
|  X  | for more information addressing perf regression bugs. For feedback,
| / \ | file a bug with label Cr-Tests-AutoBisect.  Thank you!
Cc: jam@chromium.org
eae@, there appears to have been a regression for page load time on windows 8 esp. for non-Latin-script languages (Arabic, Hewbrew, Korean, Thai, Devanagari, Chinese, ...)

This regression is much clearer on some sites than others:
http://hindi.oneindia.in
http://www.mydiyclub.com

What's special about non-Latin fonts on Windows 8?

Comment 4 by e...@chromium.org, Mar 9 2016

Status: WontFix (was: Assigned)
Nothing really. I'm guessing that before we fell back on the default settings on the windows 8 bots as we didn't have permission to read the preferences. We didn't change any of the logic, only the way we read the user settings from within the sandbox.

Certain types of AA is more expensive than others. As long as this is limited to a subset of tests for a single bot I'm not to worries. If we see this on either the win7 or win10 bots though please let me know and I'll investigate.

===== BISECT JOB RESULTS =====
Status: completed


===== SUSPECTED CL(s) =====
Subject : Pass Windows font rendering preferences from browser to blink
Author  : eae
Commit description:
  
Change the way Blink queries Windows font settings to work reliably with
the sandbox. Instead of calling SystemParametersInfo directly from Blink
in FontPlatformDataWin do so in the browser process and pass the desired
flags to Blink using the WebFontRendering interface. Also, use the value
should_antialias_text in Chrome's RendererPreferences object rather than
checking the SPI_GETFONTSMOOTHINGTYPE Windows system parameter directly.

Similarly use the subpixel_rendering field in RendererPreferences rather
than checking FE_FONTSMOOTHINGCLEARTYPE to control use of subpixel text.

In addition to ensure that these values are queried correctly this helps
guarantee that Chrome and Blink use the same setting for text rendering.

TBR=jam@chromium.org
BUG= 419003 

Review URL: https://codereview.chromium.org/1763803002

Cr-Commit-Position: refs/heads/master@{#379589}
Commit  : e3fe85330f1fbad6cb02cd0c5ceb09498e50f349
Date    : Mon Mar 07 18:22:20 2016


===== TESTED REVISIONS =====
Revision                Mean Value  Std. Dev.   Num Values  Good?
chromium@379577         1067.737    14.417007   5           good
chromium@379585         1065.2465   15.330138   5           good
chromium@379587         1080.062    19.04069    5           good
chromium@379588         1076.4325   51.899487   5           good
chromium@379589         1266.4735   16.570675   5           bad
chromium@379593         1264.5215   12.837942   5           bad
chromium@379607         1258.6865   14.782322   5           bad

Bisect job ran on: win_8_perf_bisect
Bug ID: 593102

Test Command: python src/tools/perf/run_benchmark -v --browser=release --output-format=chartjson --also-run-disabled-tests page_cycler.intl_hi_ru
Test Metric: warm_times/http___hindi.oneindia.in_
Relative Change: 17.88%
Score: 99.9

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/win_8_perf_bisect/builds/1873
Job details: https://chromeperf.appspot.com/buildbucket_job_status/9018648224360667056


| O O | Visit http://www.chromium.org/developers/speed-infra/perf-bug-faq
|  X  | for more information addressing perf regression bugs. For feedback,
| / \ | file a bug with label Cr-Tests-AutoBisect.  Thank you!

===== BISECT JOB RESULTS =====
Status: completed


===== SUSPECTED CL(s) =====
Subject : Pass Windows font rendering preferences from browser to blink
Author  : eae
Commit description:
  
Change the way Blink queries Windows font settings to work reliably with
the sandbox. Instead of calling SystemParametersInfo directly from Blink
in FontPlatformDataWin do so in the browser process and pass the desired
flags to Blink using the WebFontRendering interface. Also, use the value
should_antialias_text in Chrome's RendererPreferences object rather than
checking the SPI_GETFONTSMOOTHINGTYPE Windows system parameter directly.

Similarly use the subpixel_rendering field in RendererPreferences rather
than checking FE_FONTSMOOTHINGCLEARTYPE to control use of subpixel text.

In addition to ensure that these values are queried correctly this helps
guarantee that Chrome and Blink use the same setting for text rendering.

TBR=jam@chromium.org
BUG= 419003 

Review URL: https://codereview.chromium.org/1763803002

Cr-Commit-Position: refs/heads/master@{#379589}
Commit  : e3fe85330f1fbad6cb02cd0c5ceb09498e50f349
Date    : Mon Mar 07 18:22:20 2016


===== TESTED REVISIONS =====
Revision                Mean Value  Std. Dev.   Num Values  Good?
chromium@379577         4703.842    152.925303  5           good
chromium@379585         4609.43975  14.503894   5           good
chromium@379587         4627.8      19.878396   5           good
chromium@379588         4592.01     30.971815   5           good
chromium@379589         5330.519    22.927887   5           bad
chromium@379593         5326.02275  17.717097   5           bad
chromium@379607         5310.227    75.454717   5           bad

Bisect job ran on: win_8_perf_bisect
Bug ID: 593102

Test Command: python src/tools/perf/run_benchmark -v --browser=release --output-format=chartjson --also-run-disabled-tests page_cycler.tough_layout_cases
Test Metric: cold_times/http___mydiyclub.com
Relative Change: 12.89%
Score: 99.9

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/win_8_perf_bisect/builds/1874
Job details: https://chromeperf.appspot.com/buildbucket_job_status/9018648191595033376


| O O | Visit http://www.chromium.org/developers/speed-infra/perf-bug-faq
|  X  | for more information addressing perf regression bugs. For feedback,
| / \ | file a bug with label Cr-Tests-AutoBisect.  Thank you!

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