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Canvas performance dropped significantly for frequent re-draws, with revision 341634
Reported by
jakob....@gmail.com,
Mar 21 2016
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Issue descriptionUserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.87 Safari/537.36 Example URL: http://appcreated.de/hosting/chromium_issue_v3/ Steps to reproduce the problem: 1. Using revision 341620, go to http://appcreated.de/hosting/chromium_issue_v3/ 2. Notice the time it takes until the texts are drawn (ca. 4 seconds for me, maybe reload a few times) 3. Using revision 341634 or later, go to http://appcreated.de/hosting/chromium_issue_v3/ 4. Notice the significantly longer time it takes until the texts are drawn (ca. 12 seconds for me) What is the expected behavior? Equal or better performance with the newer revision. What went wrong? It might be that the issue is related to/caused by this canvas-related release of Blink, which appears to be in the changelog between the two revisions: https://src.chromium.org/viewvc/blink?view=revision&revision=199900 This is the complete changelog: https://chromium.googlesource.com/chromium/src/+log/4a71a24c0d566117eeec1e20968ab6f345a3c73e..da506c83c44c94f391a282e94fa4ef417861611d (--> "Roll src/third_party/WebKit...") Also refer to this discussion thread: https://groups.google.com/a/chromium.org/forum/#!topic/chromium-discuss/vCCZksLAOUY Attached source files of the provided example URL. Does it occur on multiple sites: Yes Is it a problem with a plugin? N/A Did this work before? Yes Revision 341620 Does this work in other browsers? No Safari 9.0.3 (Mac) Chrome version: 49.0.2623.87 Channel: stable OS Version: OS X 10.11.3 Flash Version: Shockwave Flash 21.0 r0 In the example, the canvas is cleared and re-drawn after each Ajax response (each single text). If we don't clear every time, the issue does not appear. Of course I know now that redrawing the whole canvas after each Ajax response is not such a good idea (this is what my local web-app did). But still, I think that we should find out what changed in Chromium to effect such a performance deterioration.
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Mar 21 2016
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Mar 21 2016
Thank you for taking the time to look into this (and bisect it manually!) Because this performs similarly in Safari (~5s) and really poor in Firefox (~30s), I think the answer may be that browsers are optimizing for different patterns and it would be better to restructure the logic. Assigning to junov to confirm and maybe see if this pattern could be made faster.
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Mar 21 2016
Thanks, I also noticed the really poor performance in Firefox yesterday :). Although I'm the author of this issue, I would assign it a relatively low priority and maybe not do anything at all. The mentioned use-case is relatively special, a little stupid, and can easily be fixed as soon as one spent the time to look into it. It was just that I already spent a good deal of my day in bisecting it, creating the example, and discussing in the group, so creating this issue ticket here was the least effortful step. I believe in the developer of the regarded Blink canvas changes and assume there are bigger benefits of the mentioned release than drawbacks. I personally would not want to risk getting regression problems in there now just because of this "small" issue.
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Mar 22 2016
Fyi I just noticed that on my MacBook Air (Early 2014) the current Chrome 49 performs quite ok (ca. 4 seconds; in contrast to my Mac Mini (Mid 2011)). But still poor performance with revision 341634. The previous revision 341620 performs well on both devices.
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Apr 18 2016
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Jun 1 2016
Moving this nonessential bug to the next milestone. For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot
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Jul 15 2016
This issue has been moved once and is lower than Pri-1. Removing the milestone. For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot
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Jul 25 2016
I tried on Mac, and it took about 5s to load the text. Looks like the issue has been fixed. Feel free to re-open if you observe this issue still exists. |
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Comment 1 by cbiesin...@chromium.org
, Mar 21 2016