Re: [PATCH] powerpc/32: Don't use lmw/stmw for saving/restoring non volatile regs

From: Michael Ellerman
Date: Tue Nov 02 2021 - 07:38:32 EST


On Mon, 23 Aug 2021 15:29:12 +0000 (UTC), Christophe Leroy wrote:
> Instructions lmw/stmw are interesting for functions that are rarely
> used and not in the cache, because only one instruction is to be
> copied into the instruction cache instead of 19. However those
> instruction are less performant than 19x raw lwz/stw as they require
> synchronisation plus one additional cycle.
>
> SAVE_NVGPRS / REST_NVGPRS are used in only a few places which are
> mostly in interrupts entries/exits and in task switch so they are
> likely already in the cache.
>
> [...]

Applied to powerpc/next.

[1/1] powerpc/32: Don't use lmw/stmw for saving/restoring non volatile regs
https://git.kernel.org/powerpc/c/a85c728cb5e12216c19ae5878980c2cbbbf8616d

cheers