Heiko Carstens 507e123151 timer stats: Optimize by adding quick check to avoid function calls ... When the kernel is configured with CONFIG_TIMER_STATS but timer stats are runtime disabled we still get calls to __timer_stats_timer_set_start_info which initializes some fields in the corresponding struct timer_list. So add some quick checks in the the timer stats setup functions to avoid function calls to __timer_stats_timer_set_start_info when timer stats are disabled. In an artificial workload that does nothing but playing ping pong with a single tcp packet via loopback this decreases cpu consumption by 1 - 1.5%. This is part of a modified function trace output on SLES11: perl-2497 [00] 28630647177732388 [+ 125]: sk_reset_timer <-tcp_v4_rcv perl-2497 [00] 28630647177732513 [+ 125]: mod_timer <-sk_reset_timer perl-2497 [00] 28630647177732638 [+ 125]: __timer_stats_timer_set_start_info <-mod_timer perl-2497 [00] 28630647177732763 [+ 125]: __mod_timer <-mod_timer perl-2497 [00] 28630647177732888 [+ 125]: __timer_stats_timer_set_start_info <-__mod_timer perl-2497 [00] 28630647177733013 [+ 93]: lock_timer_base <-__mod_timer Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Mustafa Mesanovic <mustafa.mesanovic@de.ibm.com> Cc: Arjan van de Ven <arjan@infradead.org> LKML-Reference: <20090623153811.GA4641@osiris.boeblingen.de.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>		2009-06-24 11:15:09 +02:00
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clockevents.c	Merge branch 'timers-for-linus-migration' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-06-15 10:06:19 -07:00
clocksource.c	clocksource: prevent selection of low resolution clocksourse also for nohz=on	2009-06-13 12:00:26 +02:00
jiffies.c
Kconfig
Makefile
ntp.c
tick-broadcast.c	clockevents: tick_broadcast_device can become static	2009-05-02 10:31:14 +02:00
tick-common.c	clockevents: prevent endless loop in tick_handle_periodic()	2009-05-02 10:22:27 +02:00
tick-internal.h
tick-oneshot.c	clocksource: prevent selection of low resolution clocksourse also for nohz=on	2009-06-13 12:00:26 +02:00
tick-sched.c	Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-06-20 10:51:44 -07:00
timecompare.c
timekeeping.c	Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6	2009-06-11 09:01:14 +03:00
timer_list.c
timer_stats.c	timer stats: Optimize by adding quick check to avoid function calls	2009-06-24 11:15:09 +02:00