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

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