From 597d0275736dad9c3bda6f0a00a1c477dc0f37b1 Mon Sep 17 00:00:00 2001 From: Arun R Bharadwaj Date: Thu, 16 Apr 2009 12:13:26 +0530 Subject: timers: Framework for identifying pinned timers * Arun R Bharadwaj [2009-04-16 12:11:36]: This patch creates a new framework for identifying cpu-pinned timers and hrtimers. This framework is needed because pinned timers are expected to fire on the same CPU on which they are queued. So it is essential to identify these and not migrate them, in case there are any. For regular timers, the currently existing add_timer_on() can be used queue pinned timers and subsequently mod_timer_pinned() can be used to modify the 'expires' field. For hrtimers, new modes HRTIMER_ABS_PINNED and HRTIMER_REL_PINNED are added to queue cpu-pinned hrtimer. [ tglx: use .._PINNED mode argument instead of creating tons of new functions ] Signed-off-by: Arun R Bharadwaj Signed-off-by: Thomas Gleixner --- include/linux/timer.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux/timer.h') diff --git a/include/linux/timer.h b/include/linux/timer.h index 6cdb6f3331f1..ccf882eed8f8 100644 --- a/include/linux/timer.h +++ b/include/linux/timer.h @@ -163,7 +163,10 @@ extern void add_timer_on(struct timer_list *timer, int cpu); extern int del_timer(struct timer_list * timer); extern int mod_timer(struct timer_list *timer, unsigned long expires); extern int mod_timer_pending(struct timer_list *timer, unsigned long expires); +extern int mod_timer_pinned(struct timer_list *timer, unsigned long expires); +#define TIMER_NOT_PINNED 0 +#define TIMER_PINNED 1 /* * The jiffies value which is added to now, when there is no timer * in the timer wheel: -- cgit v1.2.2 From 507e123151149e578c9aae33eb876c49824da5f8 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Tue, 23 Jun 2009 17:38:15 +0200 Subject: 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 Cc: Andrew Morton Cc: Martin Schwidefsky Cc: Mustafa Mesanovic Cc: Arjan van de Ven LKML-Reference: <20090623153811.GA4641@osiris.boeblingen.de.ibm.com> Signed-off-by: Ingo Molnar --- include/linux/timer.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux/timer.h') diff --git a/include/linux/timer.h b/include/linux/timer.h index ccf882eed8f8..be62ec2ebea5 100644 --- a/include/linux/timer.h +++ b/include/linux/timer.h @@ -190,6 +190,8 @@ extern unsigned long get_next_timer_interrupt(unsigned long now); */ #ifdef CONFIG_TIMER_STATS +extern int timer_stats_active; + #define TIMER_STATS_FLAG_DEFERRABLE 0x1 extern void init_timer_stats(void); @@ -203,6 +205,8 @@ extern void __timer_stats_timer_set_start_info(struct timer_list *timer, static inline void timer_stats_timer_set_start_info(struct timer_list *timer) { + if (likely(!timer_stats_active)) + return; __timer_stats_timer_set_start_info(timer, __builtin_return_address(0)); } -- cgit v1.2.2