Messages in this thread | | | Date | Wed, 25 Feb 2015 18:12:27 +0100 | From | Borislav Petkov <> | Subject | Some results (was: Re: [RFC PATCH] x86, fpu: Use eagerfpu by default on all CPUs) |
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On Fri, Feb 20, 2015 at 10:58:15AM -0800, Andy Lutomirski wrote: > - /* Auto enable eagerfpu for xsaveopt */ > - if (cpu_has_xsaveopt && eagerfpu != DISABLE) > + /* Auto enable eagerfpu for everyone */ > + if (eagerfpu != DISABLE) > eagerfpu = ENABLE;
So Mel did run some measurements with it on an old Intel and AMD box. Attached are netperf results from both. The Intel box is a quad core very similar to this one:
http://ark.intel.com/products/28020/Intel-Xeon-Processor-5063-4M-Cache-3_20-GHz-1066-MHz-FSB
netperf-udp-rr shows some impact of the eagerfpu patch which is outside of the noise level. netperf-tcp-rr not so much but eager is still a bit behind.
The AMD box is an old K8 and results there look like eager is better :-) Not with all though - pipetest is worse.
netperf-udp-rr is better at almost every data point and tcp-rr looks a bit useless with those high noise levels.
As a summary, the patch has some, albeit small, impact. We would need more benchmarks. We have one speccpu run which is currently taking forever to finish...
-- Regards/Gruss, Boris.
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