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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [GEN9+] 2-3% perf drop in GfxBench Manhattan 3.1 from "i965: Disable regular fast-clears (CCS_D) on gen9+""
href="https://bugs.freedesktop.org/show_bug.cgi?id=104163">104163</a>
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<th>Summary</th>
<td>[GEN9+] 2-3% perf drop in GfxBench Manhattan 3.1 from "i965: Disable regular fast-clears (CCS_D) on gen9+"
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<th>Product</th>
<td>Mesa
</td>
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<th>Version</th>
<td>git
</td>
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<th>Hardware</th>
<td>Other
</td>
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<th>OS</th>
<td>All
</td>
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<th>Status</th>
<td>NEW
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>medium
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<th>Component</th>
<td>Drivers/DRI/i965
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<th>Assignee</th>
<td>intel-3d-bugs@lists.freedesktop.org
</td>
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<th>Reporter</th>
<td>eero.t.tamminen@intel.com
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<th>QA Contact</th>
<td>intel-3d-bugs@lists.freedesktop.org
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<pre>This commit:
----------------------------------------------------
commit ee57b15ec764736e2d5360beaef9fb2045ed0f68
Author: Jason Ekstrand <<a href="mailto:jason.ekstrand@intel.com">jason.ekstrand@intel.com</a>>
AuthorDate: Wed Nov 29 16:22:42 2017 -0800
Commit: Jason Ekstrand <<a href="mailto:jason.ekstrand@intel.com">jason.ekstrand@intel.com</a>>
CommitDate: Fri Dec 1 10:14:28 2017 -0800
i965: Disable regular fast-clears (CCS_D) on gen9+
This partially reverts commit 3e57e9494c2279580ad6a83ab8c065d01e7e634e
which caused a bunch of GPU hangs on several Source titles. To date, we
have no clue why these hangs are actually happening. This undoes the
final effect of 3e57e9494c227 and gets us back to not hanging. Tested
with Team Fortress 2.
Reviewed-by: Kenneth Graunke <<a href="mailto:kenneth@whitecape.org">kenneth@whitecape.org</a>>
Bugzilla: <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - [skl,kbl] [drm] GPU HANG: ecode 9:0:0x86df7cf9, in csgo_linux64 [4947], reason: Hang on rcs, action: reset"
href="show_bug.cgi?id=102435">https://bugs.freedesktop.org/show_bug.cgi?id=102435</a>
Fixes: 3e57e9494c2279580ad6a83ab8c065d01e7e634e
Cc: <a href="mailto:mesa-stable@lists.freedesktop.org">mesa-stable@lists.freedesktop.org</a>
----------------------------------------------------
Causes following performance drops on GEN9+ (Core) platforms:
* 2-3% in GfxBench Manhattan 3.1
* 1-2% in GfxBench CarChase, SynMark v7 Deferred
* 1% in GfxBench Aztec Ruins
Only other affected test was less relevant / partly CPU bound SynMark DrvState,
it improved by 2% (because it has large number of small viewports which cause
fast-clear handling CPU overhead affect it more than memory bandwidth).
I don't have yet data from BXT, but on GLK the impact was smaller.</pre>
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