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

Michael Ellerman patch-notifications at ellerman.id.au
Tue Nov 2 21:11:45 AEDT 2021


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


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