Nouveau - May 2008 - [Bug 15845] New: X busyloops when huge image in firefox

http://bugs.freedesktop.org/show_bug.cgi?id=15845

           Summary: X busyloops when huge image in firefox
           Product: xorg
           Version: git
          Platform: x86-64 (AMD64)
        OS/Version: Linux (All)
            Status: NEW
          Severity: normal
          Priority: medium
         Component: Driver/nouveau
        AssignedTo: nouveau at lists.freedesktop.org
        ReportedBy: pq at iki.fi
         QAContact: xorg-team at lists.x.org


Created an attachment (id=16388)
 --> (http://bugs.freedesktop.org/attachment.cgi?id=16388)
Xorg log

When a huge image, e.g. 1500x3000 pixels, is shown in Firefox, any rendering
action related to that image freezes firefox for 5-10 minutes. During that time
X is eating all CPU, spending 30% in user space and 70% in kernel due to
GetTimeInMillis().

Xorg-server xorg-server-1.3.99.0-1538-gefa65a0
xf86-video-nouveau ae574ec7d930d8708e4dd9d1d47558666019afe5
DRM kernel modules drm-2.3.0-1229-g43b224f
All of them around 5.5.2008.

nouveau.ko is patched to make AGP init fail, since DFS is broken for me.

To me DRM and Xorg logs show nothing out of the ordinary.


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--- Comment #1 from Pekka Paalanen <pq at iki.fi>  2008-05-06 11:04:47 PST
---
Created an attachment (id=16389)
 --> (http://bugs.freedesktop.org/attachment.cgi?id=16389)
kernel log with debug=1


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--- Comment #2 from Pekka Paalanen <pq at iki.fi>  2008-05-06 11:16:44 PST
---
Created an attachment (id=16390)
 --> (http://bugs.freedesktop.org/attachment.cgi?id=16390)
gdb session

This is a gdb session recorded on a serial console.
For many times I interrupt X while it is spinning and print the backtrace.
There's a disassembly of nouveau_notifier_wait_status.
I set breakpoints to NVUploadToScreen and NVDownloadFromScreen to see what kind
of calls they get.

Looks like it is migrating a big pixmap a lot. w=1703, h=3000 are probably the
original dimensions of the image I used to trigger the problem this time.
During the dozens of calls to NVUploadToScreen, the firefox window does not
show any redrawing. After something like 5 mins running, the window updates
instantly, and I can re-trigger the freeze by doing anything that would expose
a piece of the huge image.

Hmm, I just noticed a pattern there:
NVUploadToScreen (pDst=0x2ba0cf4db010, x=0, y=0, w=1703, h=3000
NVUploadToScreen (pDst=0x1314020, x=0, y=0, w=494, h=1315
NVUploadToScreen (pDst=0x2ba0cf4db010, x=0, y=0, w=1703, h=3000
NVUploadToScreen (pDst=0x1314020, x=0, y=0, w=495, h=1315
NVUploadToScreen (pDst=0x2ba0cf4db010, x=0, y=0, w=1703, h=3000
NVUploadToScreen (pDst=0x1314020, x=0, y=0, w=496, h=1315
NVUploadToScreen (pDst=0x2ba0cf4db010, x=0, y=0, w=1703, h=3000
NVUploadToScreen (pDst=0x1314020, x=0, y=0, w=497, h=1315
See the width of the second pixmap.


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--- Comment #3 from Pekka Paalanen <pq at iki.fi>  2008-05-06 11:28:10 PST
---
Created an attachment (id=16391)
 --> (http://bugs.freedesktop.org/attachment.cgi?id=16391)
xorg.conf

MigrationHeuristic was not set in my xorg.conf. Setting it to "greedy"
seems to
make the problem go away.


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Pekka Paalanen <pq at iki.fi> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #16391|application/octet-stream    |text/plain
          mime type|                            |




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Pekka Paalanen <pq at iki.fi> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #16388|0                           |1
        is obsolete|                            |




--- Comment #4 from Pekka Paalanen <pq at iki.fi>  2008-05-06 13:19:04 PST
---
Created an attachment (id=16393)
 --> (http://bugs.freedesktop.org/attachment.cgi?id=16393)
X org log EXA fallback instrumentation

Includes additional instrumentation for CheckTexture and CheckBuffer.


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--- Comment #5 from Michel D?nzer <michel at tungstengraphics.com> 
2008-05-07 02:48:59 PST ---
Created an attachment (id=16408)
 --> (http://bugs.freedesktop.org/attachment.cgi?id=16408)
Only migrate in source pixmap region needed for CopyNtoN

Does this xserver patch help?

Option "EXAOptimizeMigration" might help in addition.


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--- Comment #6 from Pekka Paalanen <pq at iki.fi>  2008-05-07 12:02:16 PST
---
Michel, I applied your patch, and it indeed makes the freeze period drop from 5
minutes to just less than 1 minute. Then, adding EXAOptimizeMigration makes the
freezing go away, I don't have to wait for it to unfreeze anymore.

There were some comments on #nouveau that the braindead invocations of
NVUploadToScreen might be a Firefox 2 feature.


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Michel D?nzer <michel at tungstengraphics.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED




--- Comment #7 from Michel D?nzer <michel at tungstengraphics.com> 
2008-05-24 11:15:01 PST ---
commit 3baf3b42e079b4e7b61c1e20df305db0724d21f8
Author: Michel D??nzer <michel at tungstengraphics.com>
Date:   Sat May 24 20:01:21 2008 +0200

    EXA: Specify region used for source pixmap migration in exaCopyNtoN.

    Avoids excessive migration overhead in some pathological cases.


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