Nick Piggin beed33a816 [PATCH] sched: likely profiling ... This likely profiling is pretty fun. I found a few possible problems in sched.c. This patch may be not measurable, but when I did measure long ago, nooping (un)likely cost a couple of % on scheduler heavy benchmarks, so it all adds up. Tweak some branch hints: - the 2nd 64 bits in the bitmask is likely to be populated, because it contains the first 28 bits (nearly 3/4) of the normal priorities. (ratio of 669669:691 ~= 1000:1). - it isn't unlikely that context switching switches to another process. it might be very rapidly switching to and from the idle process (ratio of 475815:419004 and 471330:423544). Let the branch predictor decide. - preempt_enable seems to be very often called in a nested preempt_disable or with interrupts disabled (ratio of 3567760:87965 ~= 40:1) Signed-off-by: Nick Piggin <npiggin@suse.de> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: Daniel Walker <dwalker@mvista.com> Cc: Hua Zhong <hzhong@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>		2006-10-11 11:14:22 -07:00
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__ffs.h	[PATCH] bitops: generic __ffs()	2006-03-26 08:57:10 -08:00
atomic.h	[PATCH] bitops: generic {,test_and_}{set,clear,change}_bit()	2006-03-26 08:57:10 -08:00
ext2-atomic.h	[PATCH] bitops: generic ext2_{set,clear}_bit_atomic()	2006-03-26 08:57:11 -08:00
ext2-non-atomic.h	[PATCH] bitops: generic ext2_{set,clear,test,find_first_zero,find_next_zero}_bit()	2006-03-26 08:57:11 -08:00
ffs.h	[PATCH] bitops: generic ffs()	2006-03-26 08:57:11 -08:00
ffz.h	[PATCH] bitops: generic ffz()	2006-03-26 08:57:10 -08:00
find.h	[PATCH] bitops: generic find_{next,first}{,_zero}_bit()	2006-03-26 08:57:11 -08:00
fls64.h	[PATCH] fix error: __u32 undeclared	2006-03-26 08:57:11 -08:00
fls.h	[PATCH] bitops: generic fls()	2006-03-26 08:57:10 -08:00
hweight.h	[PATCH] fix error: __u32 undeclared	2006-03-26 08:57:11 -08:00
le.h	[PATCH] bitops: generic ext2_{set,clear,test,find_first_zero,find_next_zero}_bit()	2006-03-26 08:57:11 -08:00
minix-le.h	[PATCH] bitops: generic minix_{test,set,test_and_clear,test,find_first_zero}_bit()	2006-03-26 08:57:11 -08:00
minix.h	[PATCH] bitops: generic minix_{test,set,test_and_clear,test,find_first_zero}_bit()	2006-03-26 08:57:11 -08:00
non-atomic.h	[PATCH] bitops: generic __{,test_and_}{set,clear,change}_bit() and test_bit()	2006-03-26 08:57:10 -08:00
sched.h	[PATCH] sched: likely profiling	2006-10-11 11:14:22 -07:00