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beed33a816
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> |
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.. | ||
bitops | ||
4level-fixup.h | ||
atomic.h | ||
audit_change_attr.h | ||
audit_dir_write.h | ||
audit_read.h | ||
audit_write.h | ||
bitops.h | ||
bug.h | ||
cputime.h | ||
div64.h | ||
dma-mapping-broken.h | ||
dma-mapping.h | ||
emergency-restart.h | ||
errno-base.h | ||
errno.h | ||
fcntl.h | ||
futex.h | ||
ide_iops.h | ||
ioctl.h | ||
iomap.h | ||
ipc.h | ||
irq_regs.h | ||
Kbuild | ||
Kbuild.asm | ||
libata-portmap.h | ||
local.h | ||
memory_model.h | ||
mman.h | ||
mutex-dec.h | ||
mutex-null.h | ||
mutex-xchg.h | ||
page.h | ||
pci-dma-compat.h | ||
pci.h | ||
percpu.h | ||
pgtable-nopmd.h | ||
pgtable-nopud.h | ||
pgtable.h | ||
resource.h | ||
rtc.h | ||
sections.h | ||
siginfo.h | ||
signal.h | ||
statfs.h | ||
termios.h | ||
tlb.h | ||
topology.h | ||
uaccess.h | ||
unaligned.h | ||
vmlinux.lds.h | ||
xor.h |