[Bug 93864] New: Performance degradation when one display is in rotation

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=93864

            Bug ID: 93864
           Summary: Performance degradation when one display is in
                    rotation
           Product: xorg
           Version: 7.7 (2012.06)
          Hardware: x86 (IA32)
                OS: Linux (All)
            Status: NEW
          Severity: major
          Priority: medium
         Component: Driver/intel
          Assignee: chris at chris-wilson.co.uk
          Reporter: franck.delache at grassvalley.com
        QA Contact: intel-gfx-bugs at lists.freedesktop.org

My system has chipset 915GM configured in dual-display. One of the display is
configured in rotation.
I am running a Java application using XRender pipeline which does rendering at
30fps.

With Intel driver 2.99.917, the rendering is fluid and top shows about 30% of
idle CPU.
With Intel driver 2.99.917+git20151217, the rendering is not fluid and top
shows 30% in wa state (0% idle)

I managed to git bisect the culprit commit 9a311f9
sna: Throw away the TearFree damage if it grows too big

Reverting this commit makes the system behave normally (rendering is back to
30fps and CPU is 30% idle).

Note that when both displays are in normal orientation, I do not see any
performance issue.

-- 
You are receiving this mail because:
You are the QA Contact for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freedesktop.org/archives/intel-gfx-bugs/attachments/20160125/690132c8/attachment.html>