[cfe-dev] RFC: Support x86 interrupt and exception handlers

[Hal Finkel via cfe-dev]

----- Original Message -----
> From: "Joachim Durchholz via cfe-dev" <cfe-dev at lists.llvm.org>
> To: cfe-dev at lists.llvm.org
> Sent: Tuesday, September 22, 2015 3:10:56 AM
> Subject: Re: [cfe-dev] RFC: Support x86 interrupt and exception handlers
> 
> Am 22.09.2015 um 09:56 schrieb Hal Finkel:
> > The overall cost of doing the (hardware-level) mode switch can be
> > only low 10s of cycles on modern hardware,
> 
> I see. That's still quite expensive given that modern CPUs would like
> to
> execute multiple instructions per cycle.

Sure, but I imagine saving all 32 AVX registers plus the GPRs, etc. is in the same ballpark.

> More importantly, it's more
> than what I'd expect a typical interrupt stub to take but not by
> multiple orders of magnitude, so this could be just relevant enough
> to
> make a difference on an interrupt-heavy system.
> I guess it's back to "this needs to be measured to decide anything"
> :-)

I certainly agree :-)

 -Hal

> 
> Regards,
> Jo
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-- 
Hal Finkel
Assistant Computational Scientist
Leadership Computing Facility
Argonne National Laboratory