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<b><a class="bz_bug_link
bz_status_NEW "
title="NEW - 4-27% performance drop in Vulkan benchmarks"
href="https://bugs.freedesktop.org/show_bug.cgi?id=109216#c6">Comment # 6</a>
on <a class="bz_bug_link
bz_status_NEW "
title="NEW - 4-27% performance drop in Vulkan benchmarks"
href="https://bugs.freedesktop.org/show_bug.cgi?id=109216">bug 109216</a>
from <span class="vcard"><a class="email" href="mailto:lionel.g.landwerlin@linux.intel.com" title="Lionel Landwerlin <lionel.g.landwerlin@linux.intel.com>"> <span class="fn">Lionel Landwerlin</span></a>
</span></b>
<pre>(In reply to Lionel Landwerlin from <a href="show_bug.cgi?id=109216#c4">comment #4</a>)
<span class="quote">> Bisected to :
>
> commit 8fb8ebfbb05d3323481c8ba6d320b3a3580bad99
> Author: Ian Romanick <<a href="mailto:ian.d.romanick@intel.com">ian.d.romanick@intel.com</a>>
> Date: Tue May 22 18:56:41 2018 -0700
>
> intel/compiler: More peephole select
>
> Shader-db results:
>
> The one shader hurt for instructions is a compute shader that had both
> spills and fills hurt.</span >
This significantly impacts one a couple of the shaders of the multisampling
demo :
First one :
Before: SIMD16 shader: 356 instructions. 0 loops. 1812 cycles. 0:0
spills:fills. Promoted 2 constants. Compacted 5696 to 3488 bytes (39%)
After: SIMD16 shader: 157 instructions. 3 loops. 99970 cycles. 0:0
spills:fills. Promoted 2 constants. Compacted 2512 to 1536 bytes (39%)
Second one:
Before: SIMD16 shader: 249 instructions. 0 loops. 1170 cycles. 0:0
spills:fills. Promoted 0 constants. Compacted 3984 to 2560 bytes (36%)
After: SIMD16 shader: 102 instructions. 3 loops. 4580 cycles. 0:0 spills:fills.
Promoted 0 constants. Compacted 1632 to 1088 bytes (33%)
This is one of the shader :
<a href="https://github.com/SaschaWillems/Vulkan/blob/master/data/shaders/deferredmultisampling/deferred.frag">https://github.com/SaschaWillems/Vulkan/blob/master/data/shaders/deferredmultisampling/deferred.frag</a></pre>
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