Re: [PATCH 207/208] x86/fpu: Add FPU performance measurement subsystem

[Borislav Petkov]

On Tue, May 05, 2015 at 12:15:00PM -0700, Dave Hansen wrote:
> On 05/05/2015 10:58 AM, Ingo Molnar wrote:
> >   x86/fpu: Cost of: XSAVE                       insn          :   104 cycles
> >   x86/fpu: Cost of: XRSTOR                      insn          :    80 cycles
> 
> Isn't there going to be pretty huge variability here depending on how
> much state you are xsave/xrstor'ing and if the init/modified
> optimizations are in play?

If this is a module, one could modprobe/rmmod it multiple times for
an average. But yeah, it would depend in the end on what the system
does/has been doing in the recent past and thus how much state has been
"accumulated".

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
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