Bug 51862 - Shader optimizer is extremely slow
Summary: Shader optimizer is extremely slow
Status: RESOLVED NOTOURBUG
Alias: None
Product: Mesa
Classification: Unclassified
Component: Drivers/DRI/nouveau (show other bugs)
Version: git
Hardware: x86-64 (AMD64) Linux (All)
: medium critical
Assignee: Nouveau Project
QA Contact:
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Reported: 2012-07-08 05:03 UTC by Tiziano Bacocco
Modified: 2013-08-21 06:39 UTC (History)
1 user (show)

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Attachments
Comparison of shader compile times between mesa and nvidia driver (271.19 KB, image/png)
2012-07-08 05:03 UTC, Tiziano Bacocco 		Details
Profiler output while running a programm that continously compiles shaders (177.19 KB, text/plain)
2012-07-08 05:05 UTC, Tiziano Bacocco 		Details
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Description Tiziano Bacocco 2012-07-08 05:03:59 UTC 
Created attachment 63969 [details]
Comparison of shader compile times between mesa and nvidia driver

Shader optimizer is extremely slow and causes games like Crysis that loads content while playing to go very slow or freeze temporarily

On nvidia proprietary driver sometimes compiling is even 200x faster
Comment 1 Tiziano Bacocco 2012-07-08 05:05:09 UTC 
Created attachment 63970 [details]
Profiler output while running a programm that continously compiles shaders
Comment 2 Ilia Mirkin 2013-08-21 06:39:04 UTC 
Looks like most of the time is being spent in ir_expression/etc -- these are generic mesa glsl facilities. Please retest this with the latest mesa, I suspect that improvements have been made. If you still think it's slow, feel free to file a bug with the core mesa team. I don't see anything nouveau-specific about this issue. Also, please use perf for the measurements, it can see inside the kernel, which may relevant (that 16% chunk inside the kernel seems high).

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