[RFC PATCH] arm64: KVM: remove fpsimd save/restore from the world switch

Marc Zyngier marc.zyngier at arm.com
Fri Apr 10 03:08:38 PDT 2015


On 10/04/15 11:01, Peter Maydell wrote:
> On 10 April 2015 at 10:11, Marc Zyngier <marc.zyngier at arm.com> wrote:
>> I did some experimentations on arm64 a long while ago (see the
>> kvm-arm64/lazy-fp branch in my tree), and it wasn't that great,
>> apparently because aarch64 userspace tends to be much more FP happy than
>> aarch32, but I'm not completely sure about it.
> 
> Was that with the buggy version of the toolchain that had
> incorrect costs and so was much more inclined to spill
> integer values into the FPU than it should have been?
> It might be worth retesting with a freshly compiled
> userspace some day...

It definitely was with a very old toolchain and an even older userspace.
I'll respin the branch when I get some thime.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...



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