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List: kde-panel-devel
Subject: Re: Review Request: Fixing massive memory consumption in KWin using
From: "Philipp Knechtges" <philipp-dev () knechtges ! com>
Date: 2011-05-21 12:53:29
Message-ID: 20110521125329.976.90230 () vidsolbach ! de
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This is an automatically generated e-mail. To reply, visit:
http://git.reviewboard.kde.org/r/101385/
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(Updated May 21, 2011, 12:53 p.m.)
Review request for kwin and Plasma.
Changes
-------
So now every application which loads libkworkspace uses the 5*pagesize threshold.
Some numbers for plamsa-desktop:
First without patch, directly after startup:
Arena 0:
system bytes = 22970368
in use bytes = 22039088
Arena 1:
system bytes = 135168
in use bytes = 8704
Arena 2:
system bytes = 135168
in use bytes = 8480
Arena 3:
system bytes = 135168
in use bytes = 7968
Arena 4:
system bytes = 135168
in use bytes = 9472
Total (incl. mmap):
system bytes = 30732288
in use bytes = 29294960
max mmap regions = 4
max mmap bytes = 12984320
After changing theme:
Arena 0:
system bytes = 34635776
in use bytes = 25882880
Arena 1:
system bytes = 135168
in use bytes = 5568
Arena 2:
system bytes = 135168
in use bytes = 8480
Arena 3:
system bytes = 135168
in use bytes = 4832
Arena 4:
system bytes = 135168
in use bytes = 9472
Total (incl. mmap):
system bytes = 41164800
in use bytes = 31899584
max mmap regions = 4
max mmap bytes = 12984320
The numbers are not that bad as in the case of KWin.
KWin does some deep copies of QImage inside GLTexture::load, which are directly \
released afterwards. Plasma is afaik also using a pixmap cache, which starts filling \
up the unused space pretty fast.
With patch applied after theme change:
Arena 0:
system bytes = 24952832
in use bytes = 20124688
Arena 1:
system bytes = 135168
in use bytes = 5568
Arena 2:
system bytes = 135168
in use bytes = 8480
Arena 3:
system bytes = 135168
in use bytes = 4832
Arena 4:
system bytes = 135168
in use bytes = 9472
Total (incl. mmap):
system bytes = 39333888
in use bytes = 33993424
max mmap regions = 28
max mmap bytes = 17670144
as said before, the impact on plasma isnt that big as in the case of kwin.
Summary
-------
The intention of this patch is to lower the heap fragmentation in KWin when using the \
raster backend.
One can illustrate the issue with the following testcase: If one currently uses the \
raster backend and switches back to non-compositing mode one gets easily a similar \
memory usage like the following:
Situation: 14 windows, QtCurve
KWin started with compositing: 40 MB
KWin switched to non-compositing : more than 70 MB
The first guess might be, that this is due to a memleak because of not properly \
released pixmaps. But calling malloc_stats() sheds some more light on the subject \
(non-compositing mode):
Arena 0:
system bytes = 72232960
in use bytes = 8180512
Arena 1:
system bytes = 135168
in use bytes = 4784
Total (incl. mmap):
system bytes = 73080832
in use bytes = 8898000
max mmap regions = 13
max mmap bytes = 36343808
In other words, the glibc has allocated more than 70 MB memory although KWin uses \
only less than 10 MB. The problem is that glibc only resizes the heap if the heap has \
more than 128 KB of free space at the end, but many decoration pixmaps are smaller. \
Using mallopt to tune the threshold to 20 KB (i'm open for other suggestions?) fixes \
the issue. After the patch:
KWin in compositing mode: 19 MB
KWin switched to non-compositing: 13 MB
Arena 0:
system bytes = 12374016
in use bytes = 6894544
Arena 1:
system bytes = 135168
in use bytes = 4784
Total (incl. mmap):
system bytes = 13750272
in use bytes = 8140416
max mmap regions = 67
max mmap bytes = 99463168
Are there some negative effects?
The only negative effect i am aware of is, that Glibc free() is calling the sbrk \
syscall more often. But this should not be a bottleneck.
Diffs (updated)
-----
ConfigureChecks.cmake e8b64a2
config-workspace.h.cmake fabe7fa
libs/kworkspace/kworkspace.cpp 5e9afb9
libs/kworkspace/kworkspace_p.h 1f0dd3d
Diff: http://git.reviewboard.kde.org/r/101385/diff
Testing
-------
Tested using a standard Fedora 14.
Would be nice to know, whether other OSes have similar issues?
Martin Gräßlin had some concerns about the portability?
Thanks,
Philipp
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This is an automatically generated e-mail. To reply, visit:
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<br />
<table bgcolor="#fefadf" width="100%" cellspacing="0" cellpadding="8" \
style="background-image: \
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<td>
<div>Review request for kwin and Plasma.</div>
<div>By Philipp Knechtges.</div>
<p style="color: grey;"><i>Updated May 21, 2011, 12:53 p.m.</i></p>
<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Changes</h1>
<table width="100%" bgcolor="#ffffff" cellspacing="0" cellpadding="10" style="border: \
1px solid #b8b5a0"> <tr>
<td>
<pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: \
-moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: \
break-word;">So now every application which loads libkworkspace uses the 5*pagesize \
threshold.
Some numbers for plamsa-desktop:
First without patch, directly after startup:
Arena 0:
system bytes = 22970368
in use bytes = 22039088
Arena 1:
system bytes = 135168
in use bytes = 8704
Arena 2:
system bytes = 135168
in use bytes = 8480
Arena 3:
system bytes = 135168
in use bytes = 7968
Arena 4:
system bytes = 135168
in use bytes = 9472
Total (incl. mmap):
system bytes = 30732288
in use bytes = 29294960
max mmap regions = 4
max mmap bytes = 12984320
After changing theme:
Arena 0:
system bytes = 34635776
in use bytes = 25882880
Arena 1:
system bytes = 135168
in use bytes = 5568
Arena 2:
system bytes = 135168
in use bytes = 8480
Arena 3:
system bytes = 135168
in use bytes = 4832
Arena 4:
system bytes = 135168
in use bytes = 9472
Total (incl. mmap):
system bytes = 41164800
in use bytes = 31899584
max mmap regions = 4
max mmap bytes = 12984320
The numbers are not that bad as in the case of KWin.
KWin does some deep copies of QImage inside GLTexture::load, which are directly \
released afterwards. Plasma is afaik also using a pixmap cache, which starts filling \
up the unused space pretty fast.
With patch applied after theme change:
Arena 0:
system bytes = 24952832
in use bytes = 20124688
Arena 1:
system bytes = 135168
in use bytes = 5568
Arena 2:
system bytes = 135168
in use bytes = 8480
Arena 3:
system bytes = 135168
in use bytes = 4832
Arena 4:
system bytes = 135168
in use bytes = 9472
Total (incl. mmap):
system bytes = 39333888
in use bytes = 33993424
max mmap regions = 28
max mmap bytes = 17670144
as said before, the impact on plasma isnt that big as in the case of kwin.
</pre>
</td>
</tr>
</table>
<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Description </h1>
<table width="100%" bgcolor="#ffffff" cellspacing="0" cellpadding="10" style="border: \
1px solid #b8b5a0"> <tr>
<td>
<pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: \
-moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: \
break-word;">The intention of this patch is to lower the heap fragmentation in KWin \
when using the raster backend.
One can illustrate the issue with the following testcase: If one currently uses the \
raster backend and switches back to non-compositing mode one gets easily a similar \
memory usage like the following:
Situation: 14 windows, QtCurve
KWin started with compositing: 40 MB
KWin switched to non-compositing : more than 70 MB
The first guess might be, that this is due to a memleak because of not properly \
released pixmaps. But calling malloc_stats() sheds some more light on the subject \
(non-compositing mode):
Arena 0:
system bytes = 72232960
in use bytes = 8180512
Arena 1:
system bytes = 135168
in use bytes = 4784
Total (incl. mmap):
system bytes = 73080832
in use bytes = 8898000
max mmap regions = 13
max mmap bytes = 36343808
In other words, the glibc has allocated more than 70 MB memory although KWin uses \
only less than 10 MB. The problem is that glibc only resizes the heap if the heap has \
more than 128 KB of free space at the end, but many decoration pixmaps are smaller. \
Using mallopt to tune the threshold to 20 KB (i'm open for other suggestions?) \
fixes the issue. After the patch:
KWin in compositing mode: 19 MB
KWin switched to non-compositing: 13 MB
Arena 0:
system bytes = 12374016
in use bytes = 6894544
Arena 1:
system bytes = 135168
in use bytes = 4784
Total (incl. mmap):
system bytes = 13750272
in use bytes = 8140416
max mmap regions = 67
max mmap bytes = 99463168
Are there some negative effects?
The only negative effect i am aware of is, that Glibc free() is calling the sbrk \
syscall more often. But this should not be a bottleneck.</pre>
</td>
</tr>
</table>
<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Testing </h1>
<table width="100%" bgcolor="#ffffff" cellspacing="0" cellpadding="10" style="border: \
1px solid #b8b5a0"> <tr>
<td>
<pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: \
-moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: \
break-word;">Tested using a standard Fedora 14. Would be nice to know, whether other \
OSes have similar issues? Martin Gräßlin had some concerns about the \
portability?</pre> </td>
</tr>
</table>
<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Diffs</b> \
(updated)</h1> <ul style="margin-left: 3em; padding-left: 0;">
<li>ConfigureChecks.cmake <span style="color: grey">(e8b64a2)</span></li>
<li>config-workspace.h.cmake <span style="color: grey">(fabe7fa)</span></li>
<li>libs/kworkspace/kworkspace.cpp <span style="color: grey">(5e9afb9)</span></li>
<li>libs/kworkspace/kworkspace_p.h <span style="color: grey">(1f0dd3d)</span></li>
</ul>
<p><a href="http://git.reviewboard.kde.org/r/101385/diff/" style="margin-left: \
3em;">View Diff</a></p>
</td>
</tr>
</table>
</div>
</body>
</html>
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