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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - 4% performance drop in GLB 2.7 Egypt from "Use a 565 format for GL_RGB and GL_UNSIGNED_SHORT_5_6_5 textures""
href="https://bugs.freedesktop.org/show_bug.cgi?id=103939">103939</a>
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<th>Summary</th>
<td>4% performance drop in GLB 2.7 Egypt from "Use a 565 format for GL_RGB and GL_UNSIGNED_SHORT_5_6_5 textures"
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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
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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
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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>Following commit was bisected (on SKL GT2) to be cause for a performance drop
in GLB 2.7 Egypt onscreen and offscreen tests:
-------------------------------------------------------------
commit 18bdf73556440ca2eaac2d22e1e3ebe1be7b6c1d
Author: Kenneth Graunke <<a href="mailto:kenneth@whitecape.org">kenneth@whitecape.org</a>>
AuthorDate: Wed Oct 4 01:08:37 2017 -0700
Commit: Kenneth Graunke <<a href="mailto:kenneth@whitecape.org">kenneth@whitecape.org</a>>
CommitDate: Thu Oct 5 14:30:47 2017 -0700
mesa: Use a 565 format for GL_RGB and GL_UNSIGNED_SHORT_5_6_5 textures.
Found while trying to optimize an application.
Not observed to help performance on i965, but should at least reduce
the memory usage of such textures a bit.
Reviewed-by: Eric Anholt <<a href="mailto:eric@anholt.net">eric@anholt.net</a>>
Tested-by: Eero Tamminen <<a href="mailto:eero.t.tamminen@intel.com">eero.t.tamminen@intel.com</a>>
-------------------------------------------------------------
Egypt performance drop is clearly visible on following platforms:
* 4% on BSW N3050 & SKL GT2 & KBL GT2
* 2% on BXT J4205 & HSW GT2 & SKL GT4e
* 2% on BYT N2820 (only offscreen version)
(BSW & BYT have 1-channel memory, others 2-channel.)
On some other platforms the performance also increases, as was expected:
* 3% on BDW GT3
* 1% on BDW GT2 & SNB GT2 (only offscreen version)
(Sorry for filing this so late. I had been waiting to see whether blorp rework
/ texture RBC would affect this, but forgot it. That didn't affect Egypt.)</pre>
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