Subject: Re: [07/13] powerpc/64s: idle avoid SRR usage in idle sleep/wake paths

From: Michael Ellerman <[email-masked]>
Date: Mon, 19 Jun 2017 22:25:45 +1000 (AEST)

On Tue, 2017-06-13 at 13:05:51 UTC, Nicholas Piggin wrote:
> Idle code now always runs at the 0xc... effective address whether
> in real or virtual mode. This means rfid can be ditched, along
> with a lot of SRR manipulations.
> 
> In the wakeup path, carry SRR1 around in r12. Use mtmsrd to change
> MSR states as required.
> 
> This also balances the return prediction for the idle call, by
> doing blr rather than rfid to return to the idle caller.
> 
> On POWER9, 2-process context switch on different cores, with snooze
> disabled, increases performance by 2%.

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/9d29250136f60438fc0839871bae0a

cheers