From 82f67cd9fca8c8762c15ba7ed0d5747588c1e221 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Fri, 16 Feb 2007 01:28:13 -0800 Subject: [PATCH] Add debugging feature /proc/timer_stat Add /proc/timer_stats support: debugging feature to profile timer expiration. Both the starting site, process/PID and the expiration function is captured. This allows the quick identification of timer event sources in a system. Sample output: # echo 1 > /proc/timer_stats # cat /proc/timer_stats Timer Stats Version: v0.1 Sample period: 4.010 s 24, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick) 11, 0 swapper sk_reset_timer (tcp_delack_timer) 6, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick) 2, 1 swapper queue_delayed_work_on (delayed_work_timer_fn) 17, 0 swapper hrtimer_restart_sched_tick (hrtimer_sched_tick) 2, 1 swapper queue_delayed_work_on (delayed_work_timer_fn) 4, 2050 pcscd do_nanosleep (hrtimer_wakeup) 5, 4179 sshd sk_reset_timer (tcp_write_timer) 4, 2248 yum-updatesd schedule_timeout (process_timeout) 18, 0 swapper hrtimer_restart_sched_tick (hrtimer_sched_tick) 3, 0 swapper sk_reset_timer (tcp_delack_timer) 1, 1 swapper neigh_table_init_no_netlink (neigh_periodic_timer) 2, 1 swapper e1000_up (e1000_watchdog) 1, 1 init schedule_timeout (process_timeout) 100 total events, 25.24 events/sec [ cleanups and hrtimers support from Thomas Gleixner ] [bunk@stusta.de: nr_entries can become static] Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner Cc: john stultz Cc: Roman Zippel Cc: Andi Kleen Signed-off-by: Adrian Bunk Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/Kconfig.debug | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'lib') diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 63f04c15e6f5..4448f91b865c 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -134,6 +134,17 @@ config SCHEDSTATS application, you can say N to avoid the very slight overhead this adds. +config TIMER_STATS + bool "Collect kernel timers statistics" + depends on DEBUG_KERNEL && PROC_FS + help + If you say Y here, additional code will be inserted into the + timer routines to collect statistics about kernel timers being + reprogrammed. The statistics can be read from /proc/timer_stats. + The statistics collection is started by writing 1 to /proc/timer_stats, + writing 0 stops it. This feature is useful to collect information + about timer usage patterns in kernel and userspace. + config DEBUG_SLAB bool "Debug slab memory allocations" depends on DEBUG_KERNEL && SLAB -- cgit v1.2.3