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<base href="https://bugs.freedesktop.org/" />
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<th>Priority</th>
<td>medium
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<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - cairo-perf does not deal with cpus larger then 1024 well."
href="https://bugs.freedesktop.org/show_bug.cgi?id=66783">66783</a>
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<th>Assignee</th>
<td>chris@chris-wilson.co.uk
</td>
</tr>
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<th>Summary</th>
<td>cairo-perf does not deal with cpus larger then 1024 well.
</td>
</tr>
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<th>QA Contact</th>
<td>cairo-bugs@cairographics.org
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Classification</th>
<td>Unclassified
</td>
</tr>
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<th>OS</th>
<td>Linux (All)
</td>
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<th>Reporter</th>
<td>nzimmer@sgi.com
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<th>Hardware</th>
<td>Other
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Version</th>
<td>1.12.14
</td>
</tr>
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<th>Component</th>
<td>general
</td>
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<th>Product</th>
<td>cairo
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<p>
<div>
<pre>The function check_cpu_affinity (void) can return incorrect results.
This function is attempting to confirm that the process is only running on a
single cpu. On a large box it can report success where it should have failed.
For example if it has affinity with cpus 600, 1200 check_cpu_affinity will
report it is ok when that true.
This issue is that CPU_SETSIZE on some distros is 1024, but the kernel is quite
capable of handling 4096 cpus.
The code in question is here.
cpu_set_t affinity
for(i = 0, cpu_count = 0; i < CPU_SETSIZE; ++i) {
if (CPU_ISSET(i, &affinity))
++cpu_count;
}</pre>
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