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<body><span class="vcard"><a class="email" href="mailto:chris@chris-wilson.co.uk" title="Chris Wilson <chris@chris-wilson.co.uk>"> <span class="fn">Chris Wilson</span></a>
</span> changed
<a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - [ilk] igt/gem_close_race is slow due to mutex contention vs clflush"
href="https://bugs.freedesktop.org/show_bug.cgi?id=71029">bug 71029</a>
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<table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>What</th>
<th>Removed</th>
<th>Added</th>
</tr>
<tr>
<td style="text-align:right;">Status</td>
<td>REOPENED
</td>
<td>RESOLVED
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<td style="text-align:right;">Resolution</td>
<td>---
</td>
<td>FIXED
</td>
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<b><a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - [ilk] igt/gem_close_race is slow due to mutex contention vs clflush"
href="https://bugs.freedesktop.org/show_bug.cgi?id=71029#c21">Comment # 21</a>
on <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - [ilk] igt/gem_close_race is slow due to mutex contention vs clflush"
href="https://bugs.freedesktop.org/show_bug.cgi?id=71029">bug 71029</a>
from <span class="vcard"><a class="email" href="mailto:chris@chris-wilson.co.uk" title="Chris Wilson <chris@chris-wilson.co.uk>"> <span class="fn">Chris Wilson</span></a>
</span></b>
<pre>commit 98165d60bec04d258eeb9623550e58a8bc2f3906
Author: Chris Wilson <<a href="mailto:chris@chris-wilson.co.uk">chris@chris-wilson.co.uk</a>>
Date: Fri Jul 11 23:36:15 2014 +0100
igt/gem_close_race: Trim object size
The challenge here is to race GPU activity versus the gem_close. Using a
large objects makes the window of GPU activity larger - except on !llc
systems we then incur massive overhead from clflush, likely destroying
any race (due to mutex contention). And that mutex contention is
amplified by the number of cores - bad news for Baytrail.
Give up and make the objects smaller and hope that the test is run
frequently enough to catch the race.
References: <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - [ilk] igt/gem_close_race is slow due to mutex contention vs clflush"
href="show_bug.cgi?id=71029">https://bugs.freedesktop.org/show_bug.cgi?id=71029</a>
Signed-off-by: Chris Wilson <<a href="mailto:chris@chris-wilson.co.uk">chris@chris-wilson.co.uk</a>></pre>
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