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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 - [CI] igt@perf_pmu@multi-client-vecs0 - fail - Failed assertion: (double)(val[1]) <= (1.0 + (tolerance)) * (double)(slept) && (double)(val[1]) >= (1.0 - (tolerance)) * (double)(slept)"
href="https://bugs.freedesktop.org/show_bug.cgi?id=103886">bug 103886</a>
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<table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>What</th>
<th>Removed</th>
<th>Added</th>
</tr>
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<td style="text-align:right;">Resolution</td>
<td>---
</td>
<td>FIXED
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<td style="text-align:right;">Status</td>
<td>NEW
</td>
<td>RESOLVED
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<b><a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - [CI] igt@perf_pmu@multi-client-vecs0 - fail - Failed assertion: (double)(val[1]) <= (1.0 + (tolerance)) * (double)(slept) && (double)(val[1]) >= (1.0 - (tolerance)) * (double)(slept)"
href="https://bugs.freedesktop.org/show_bug.cgi?id=103886#c1">Comment # 1</a>
on <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - [CI] igt@perf_pmu@multi-client-vecs0 - fail - Failed assertion: (double)(val[1]) <= (1.0 + (tolerance)) * (double)(slept) && (double)(val[1]) >= (1.0 - (tolerance)) * (double)(slept)"
href="https://bugs.freedesktop.org/show_bug.cgi?id=103886">bug 103886</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>Final cleanup (we hope):
commit 8ee4f19c47031f23340055da4d9f2af537de23f4
Author: Tvrtko Ursulin <<a href="mailto:tvrtko.ursulin@intel.com">tvrtko.ursulin@intel.com</a>>
Date: Fri Nov 24 09:49:59 2017 +0000
drm/i915/pmu: Stop averaging with the previous sample
Averaging with the previous sample brings a small statistical improvement
to sampling counters, but can leek a little bit of state from a current
client to the next which mulls the border between past and present for
observing clients.
This is because on event enable clients record the current counter value
and use it as reference, but with rapid off-on event cycles, and due the
delayed nature of sampling timer self-disarm, previous sample value does
not get cleared under these circumstances.
Solution is to stop averaging with the previous sample. This has a small
downside of losing some precision with short and spiky signals, but the
alternatives look too complicated for the benefit.
Signed-off-by: Tvrtko Ursulin <<a href="mailto:tvrtko.ursulin@intel.com">tvrtko.ursulin@intel.com</a>>
Cc: Chris Wilson <<a href="mailto:chris@chris-wilson.co.uk">chris@chris-wilson.co.uk</a>>
Cc: Sagar Arun Kamble <<a href="mailto:sagar.a.kamble@intel.com">sagar.a.kamble@intel.com</a>>
Reviewed-by: Chris Wilson <<a href="mailto:chris@chris-wilson.co.uk">chris@chris-wilson.co.uk</a>>
Tested-by: Chris Wilson <<a href="mailto:chris@chris-wilson.co.uk">chris@chris-wilson.co.uk</a>>
Link:
<a href="https://patchwork.freedesktop.org/patch/msgid/20171124094959.10725-1-tvrtko.ursulin@linux.intel.com">https://patchwork.freedesktop.org/patch/msgid/20171124094959.10725-1-tvrtko.ursulin@linux.intel.com</a></pre>
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