Re: [PATCH v4 1/8] powerpc/32: Add VDSO version of getcpu on non SMP
From: Michael Ellerman
Date: Wed Jan 29 2020 - 00:18:31 EST
On Mon, 2019-12-02 at 07:57:27 UTC, Christophe Leroy wrote:
> Commit 18ad51dd342a ("powerpc: Add VDSO version of getcpu") added
> getcpu() for PPC64 only, by making use of a user readable general
> purpose SPR.
>
> PPC32 doesn't have any such SPR.
>
> For non SMP, just return CPU id 0 from the VDSO directly.
> PPC32 doesn't support CONFIG_NUMA so NUMA node is always 0.
>
> Before the patch, vdsotest reported:
> getcpu: syscall: 1572 nsec/call
> getcpu: libc: 1787 nsec/call
> getcpu: vdso: not tested
>
> Now, vdsotest reports:
> getcpu: syscall: 1582 nsec/call
> getcpu: libc: 502 nsec/call
> getcpu: vdso: 187 nsec/call
>
> Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
Patches 1, 2 and 4-8, applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/902137ba8e469ed07c7f120a390161937a6288fb
cheers