tick management: spread timer interrupt
authorjohn stultz <johnstul@us.ibm.com>
Sat, 21 Jul 2007 11:37:35 +0000 (04:37 -0700)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>
Sun, 22 Jul 2007 00:49:15 +0000 (17:49 -0700)
commit3704540b48295253bd9c87a5e7ff545f9d47a3b8
tree081647bba6b901bfaa7e7216ed2f23c42ecee75d
parent5590a536c0bc403fc73908c66c1c88cbed735ecb
tick management: spread timer interrupt

After discussing w/ Thomas over IRC, it seems the issue is the sched tick
fires on every cpu at the same time, causing extra lock contention.

This smaller change, adds an extra offset per cpu so the ticks don't line up.
This patch also drops the idle latency from 40us down to under 20us.

Signed-off-by: john stultz <johnstul@us.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kernel/time/tick-sched.c