From: Tim Blechmann <tim@klingt.org>
To: linux-kernel@vger.kernel.org, x86@kernel.org
Subject: [PATCH] sched, x86: Optimize branch hint in __switch_to()
Date: Sun, 29 Nov 2009 12:55:16 +0100 [thread overview]
Message-ID: <4B126124.60902@klingt.org> (raw)
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Branch hint profiling on my nehalem machine showed 89%
incorrect branch hints:
31032542 270070841 89 __switch_to process_64.c 440
Signed-off-by: Tim Blechmann <tim@klingt.org>
---
arch/x86/kernel/process_64.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
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diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index c8d0ece..88068b3 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -437,7 +437,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
* reload when it has changed. When prev process used 64bit
* base always reload to avoid an information leak.
*/
- if (unlikely(fsindex | next->fsindex | prev->fs)) {
+ if (fsindex | next->fsindex | prev->fs) {
loadsegment(fs, next->fsindex);
/*
* Check if the user used a selector != 0; if yes
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reply other threads:[~2009-11-29 11:55 UTC|newest]
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