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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2009-07-21 20:25:05 +0200
committerIngo Molnar <mingo@elte.hu>2009-08-04 20:28:25 +0200
commit97fd9ed48ce2b807edc363bef3e817aeeb5cd5e6 (patch)
treeffb221aba4444bd3a1f84affd2aba7aa0784484e /kernel/pid.c
parentfbd90375d7531927d312766b548376d909811b4d (diff)
downloadlinux-97fd9ed48ce2b807edc363bef3e817aeeb5cd5e6.tar.bz2
timers: Cache __next_timer_interrupt result
Each time a cpu goes to sleep on a NOHZ=y system the timer wheel is searched for the next timer interrupt. It can take quite a few cycles to find the next pending timer. This patch adds a field to tvec_base that caches the result of __next_timer_interrupt. The hit ratio is around 80% on my thinkpad under normal use, on a server I've seen hit ratios from 5% to 95% dependent on the workload. -v2: jiffies wrap fixes Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Cc: Venki Pallipadi <venkatesh.pallipadi@intel.com> LKML-Reference: <20090721202505.7d56a079@skybase> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/pid.c')
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