Message ID | 1474806941-5006-1-git-send-email-anton@ozlabs.org (mailing list archive) |
---|---|
State | Accepted |
Headers | show |
On Sun, 2016-09-25 at 22:35 +1000, Anton Blanchard wrote: > From: Anton Blanchard <anton@samba.org> > > POWER8 handles unaligned accesses in little endian mode, but commit > 0b5e6661ac69 ("powerpc: Don't set HAVE_EFFICIENT_UNALIGNED_ACCESS on > little endian builds") disabled it for all. > > The issue with unaligned little endian accesses is specific to > POWER7, > so update the Kconfig check to match. Using the stat() testcase from > commit a75c380c7129 ("powerpc: Enable DCACHE_WORD_ACCESS on > ppc64le"), > performance improves 15% on POWER8. Hrm.. this should really be a runtime switch... > Signed-off-by: Anton Blanchard <anton@samba.org> > --- > arch/powerpc/Kconfig | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig > index 0a70c86..04c447d 100644 > --- a/arch/powerpc/Kconfig > +++ b/arch/powerpc/Kconfig > @@ -96,7 +96,7 @@ config PPC > select VIRT_TO_BUS if !PPC64 > select HAVE_IDE > select HAVE_IOREMAP_PROT > - select HAVE_EFFICIENT_UNALIGNED_ACCESS if !CPU_LITTLE_ENDIAN > + select HAVE_EFFICIENT_UNALIGNED_ACCESS if > !(CPU_LITTLE_ENDIAN && POWER7_CPU) > select HAVE_KPROBES > select HAVE_ARCH_KGDB > select HAVE_KRETPROBES
Hi Ben,
> Hrm.. this should really be a runtime switch...
I wonder if anyone is still running POWER7 LE, perhaps we could drop it
entirely.
Anton
On Sun, 2016-25-09 at 12:35:40 UTC, Anton Blanchard wrote: > From: Anton Blanchard <anton@samba.org> > > POWER8 handles unaligned accesses in little endian mode, but commit > 0b5e6661ac69 ("powerpc: Don't set HAVE_EFFICIENT_UNALIGNED_ACCESS on > little endian builds") disabled it for all. > > The issue with unaligned little endian accesses is specific to POWER7, > so update the Kconfig check to match. Using the stat() testcase from > commit a75c380c7129 ("powerpc: Enable DCACHE_WORD_ACCESS on ppc64le"), > performance improves 15% on POWER8. > > Signed-off-by: Anton Blanchard <anton@samba.org> Series applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/8a18cc0c2c36ee49d70a620ac0190d cheers
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 0a70c86..04c447d 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -96,7 +96,7 @@ config PPC select VIRT_TO_BUS if !PPC64 select HAVE_IDE select HAVE_IOREMAP_PROT - select HAVE_EFFICIENT_UNALIGNED_ACCESS if !CPU_LITTLE_ENDIAN + select HAVE_EFFICIENT_UNALIGNED_ACCESS if !(CPU_LITTLE_ENDIAN && POWER7_CPU) select HAVE_KPROBES select HAVE_ARCH_KGDB select HAVE_KRETPROBES