Ubuntu
compiz package

compiz "sync to vblank" causes high cpu and poor performance for OpenGL applications

Bug #1055154 reported by Alex Baines on 2012-09-23

This bug report is a duplicate of: Bug #1051286: [performance] glXSwapIntervalEXT called every frame, which is very slow on Nvidia.. Edit Remove

This bug affects 3 people

Affects		Status	Importance	Assigned to	Milestone
	compiz (Ubuntu)	Confirmed	Undecided	Unassigned

Bug Description

When using the compiz window manager (version 0.9.7.8) with the "sync to vblank" option enabled in the OpenGL plugin section of CCSM, OpenGL applications will cause the CPU usage of Xorg and compiz to be very high, and the application's frame rate will be stuttering.

I have pinpointed this issue to a line in compiz/plugins/opengl/src/screen.cpp which I believe is calling glXSwapIntervalSGI(0) every frame unecessarily, leading to poor performance.

I have attached a patch which comments the line in question out, and fixes this issue.

My system is running Ubuntu 12.04 with an Nvidia 560TI graphics card, I've tried several nvidia proprietary drivers (295.40, 295.33, 304.43) which all have this issue, and which the attached compiz patch fixes.

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Revision history for this message

Alex Baines (abaines) wrote on 2012-09-23:

Patch for compiz to fix the described issue. Edit (424 bytes, text/plain)

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Ubuntu Foundations Team Bug Bot (crichton) wrote on 2012-09-23:

The attachment "Patch for compiz to fix the described issue." of this bug report has been identified as being a patch. The ubuntu-reviewers team has been subscribed to the bug report so that they can review the patch. In the event that this is in fact not a patch you can resolve this situation by removing the tag 'patch' from the bug report and editing the attachment so that it is not flagged as a patch. Additionally, if you are member of the ubuntu-reviewers team please also unsubscribe the team from this bug report.

[This is an automated message performed by a Launchpad user owned by Brian Murray. Please contact him regarding any issues with the action taken in this bug report.]

tags:

added: patch

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Daniel van Vugt (vanvugt) wrote on 2012-09-24:

Thank you for taking the time to report this bug and helping to make Ubuntu better. This particular bug has already been reported and is a duplicate of bug 1051286, so it is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Feel free to continue to report any other bugs you may find.

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Launchpad Janitor (janitor) wrote on 2013-07-19:

Status changed to 'Confirmed' because the bug affects multiple users.