From: Anton Blanchard <anton@ozlabs.org>
To: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au,
npiggin@gmail.com
Cc: linuxppc-dev@lists.ozlabs.org
Subject: [PATCH 1/2] powerpc: Only disable HAVE_EFFICIENT_UNALIGNED_ACCESS on POWER7 little endian
Date: Sun, 25 Sep 2016 22:35:40 +1000 [thread overview]
Message-ID: <1474806941-5006-1-git-send-email-anton@ozlabs.org> (raw)
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>
---
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
--
2.7.4
next reply other threads:[~2016-09-25 12:35 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-25 12:35 Anton Blanchard [this message]
2016-09-25 12:35 ` [PATCH 2/2] powerpc: Set default CPU type to POWER8 for little endian builds Anton Blanchard
2016-09-25 22:45 ` [PATCH 1/2] powerpc: Only disable HAVE_EFFICIENT_UNALIGNED_ACCESS on POWER7 little endian Benjamin Herrenschmidt
2016-09-25 23:07 ` Anton Blanchard
2016-10-05 2:36 ` [1/2] " Michael Ellerman
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