Red Hat Bugzilla – Bug 181913
[x86_64] excessive debug messages kill 3D performance for i945G
Last modified: 2007-11-30 17:07:23 EST
Description of problem:
When the i915 kernel module is present, Xorg turns on 3D features;
but this generates debug messages in mesa. This turns glxgears
performance down to about 22fps from about 1000fps (accelerated)
or 800fps (unaccelerated).
Version-Release number of selected component (if applicable):
Install xorg-x11 and related rpms, then boot with an x86_64 kernel
that has the i915 drm module. Run glxgears from a terminal
and observe the spew. Redirect stderr to /dev/null, hiding
the spew, and see the very low performance numbers...
Debugging spew and awful 3D performance
No messages on stderr in the absense of errors,
and respectable 3D performance.
This issue was first raised in RHEL4-U3. Xorg is covered
in bug 170517, and the kernel in 173882.
A patch exists here:
Kernel support for i915 under x86_64 needs to be added to trigger
this problem; bug 181912 covers that issue.
*** Bug 158016 has been marked as a duplicate of this bug. ***
Patch xorg-x11-6.8.2-mesa-i915-squelch-debug-spew.patch added to test
candidate for U4.
Please test the xorg-x11-6.8.2-1.EL.13.26 packages available for download via
FTP at: ftp://people.redhat.com/mharris/testing/4E/xorg-x11
Setting bug to MODIFIED state as per comment #5
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.