Subject: Re: [01/19] powerpc: Don't disable kernel FP/VMX/VSX MSR bits on context switch

From: Michael Ellerman <[email-masked]>
Date: Mon, 7 Dec 2015 21:30:47 +1100 (AEDT)

On Thu, 2015-29-10 at 00:43:53 UTC, Anton Blanchard wrote:
> Writing the MSR is slow, so we want to avoid it whenever possible.
> 
> A subsequent patch will add a debug option that strictly manages the
> FP/VMX/VSX unavailable bits. For now just remove it, matching what
> we do in other areas of the kernel (eg enable_kernel_altivec()).
> 
> A context switch microbenchmark using yield():
> 
> http://ozlabs.org/~anton/junkcode/context_switch2.c
> 
> ./context_switch2 --test=yield --fp 0 0
> 
> shows an improvement of almost 3% on POWER8.
> 
> Signed-off-by: Anton Blanchard <[email-masked]>

Applied all 19 patches to powerpc next, thanks.

http://git.kernel.org/cgit/linux/kernel/git/powerpc/linux.git/log/?h=next

cheers