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authorTim Blechmann <tim@klingt.org>2009-11-24 11:55:15 +0100
committerIngo Molnar <mingo@elte.hu>2009-11-24 12:20:04 +0100
commita3a1de0c34de6f5f8332cd6151c46af7813c0fcb (patch)
tree2eaff67aaf2e0c841b26054b48e2a632db211c40 /arch/x86
parent710390d90f143a9ebb87a475215140f426792efd (diff)
sched, x86: Optimize branch hint in __switch_to()
Branch hint profiling on my nehalem machine showed 96% incorrect branch hints: 6548732 174664120 96 __switch_to process_64.c 406 6548745 174565593 96 __switch_to process_64.c 410 Signed-off-by: Tim Blechmann <tim@klingt.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <4B0BBB93.3080307@klingt.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kernel/process_64.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index ad535b68317..d9db1049e86 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -406,11 +406,10 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
* This won't pick up thread selector changes, but I guess that is ok.
*/
savesegment(es, prev->es);
- if (unlikely(next->es | prev->es))
+ if (next->es | prev->es)
loadsegment(es, next->es);
-
savesegment(ds, prev->ds);
- if (unlikely(next->ds | prev->ds))
+ if (next->ds | prev->ds)
loadsegment(ds, next->ds);