From 352ad25aa4a189c667cb2af333948d34692a2d27 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 12 May 2008 21:20:42 +0200 Subject: ftrace: tracer for scheduler wakeup latency This patch adds the tracer that tracks the wakeup latency of the highest priority waking task. "wakeup" is added to /debugfs/tracing/available_tracers Also added to /debugfs/tracing tracing_max_latency holds the current max latency for the wakeup wakeup_thresh if set to other than zero, a log will be recorded for every wakeup that takes longer than the number entered in here (usecs for all counters) (deletes previous trace) Examples: (with ftrace_enabled = 0) ============ preemption latency trace v1.1.5 on 2.6.24-rc8 Signed-off-by: Ingo Molnar -------------------------------------------------------------------- latency: 26 us, #2/2, CPU#1 | (M:rt VP:0, KP:0, SP:0 HP:0 #P:2) ----------------- | task: migration/0-3 (uid:0 nice:-5 policy:1 rt_prio:99) ----------------- _------=> CPU# / _-----=> irqs-off | / _----=> need-resched || / _---=> hardirq/softirq ||| / _--=> preempt-depth |||| / ||||| delay cmd pid ||||| time | caller \ / ||||| \ | / quilt-8551 0d..3 0us+: wake_up_process+0x15/0x17 (sched_exec+0xc9/0x100 ) quilt-8551 0d..4 26us : sched_switch_callback+0x73/0x81 (schedule+0x483/0x6d5 ) vim:ft=help ============ (with ftrace_enabled = 1) ============ preemption latency trace v1.1.5 on 2.6.24-rc8 -------------------------------------------------------------------- latency: 36 us, #45/45, CPU#0 | (M:rt VP:0, KP:0, SP:0 HP:0 #P:2) ----------------- | task: migration/1-5 (uid:0 nice:-5 policy:1 rt_prio:99) ----------------- _------=> CPU# / _-----=> irqs-off | / _----=> need-resched || / _---=> hardirq/softirq ||| / _--=> preempt-depth |||| / ||||| delay cmd pid ||||| time | caller \ / ||||| \ | / bash-10653 1d..3 0us : wake_up_process+0x15/0x17 (sched_exec+0xc9/0x100 ) bash-10653 1d..3 1us : try_to_wake_up+0x271/0x2e7 (sub_preempt_count+0xc/0x7a ) bash-10653 1d..2 2us : try_to_wake_up+0x296/0x2e7 (update_rq_clock+0x9/0x20 ) bash-10653 1d..2 2us : update_rq_clock+0x1e/0x20 (__update_rq_clock+0xc/0x90 ) bash-10653 1d..2 3us : __update_rq_clock+0x1b/0x90 (sched_clock+0x9/0x29 ) bash-10653 1d..2 4us : try_to_wake_up+0x2a6/0x2e7 (activate_task+0xc/0x3f ) bash-10653 1d..2 4us : activate_task+0x2d/0x3f (enqueue_task+0xe/0x66 ) bash-10653 1d..2 5us : enqueue_task+0x5b/0x66 (enqueue_task_rt+0x9/0x3c ) bash-10653 1d..2 6us : try_to_wake_up+0x2ba/0x2e7 (check_preempt_wakeup+0x12/0x99 ) [...] bash-10653 1d..5 33us : tracing_record_cmdline+0xcf/0xd4 (_spin_unlock+0x9/0x33 ) bash-10653 1d..5 34us : _spin_unlock+0x19/0x33 (sub_preempt_count+0xc/0x7a ) bash-10653 1d..4 35us : wakeup_sched_switch+0x65/0x2ff (_spin_lock_irqsave+0xc/0xa9 ) bash-10653 1d..4 35us : _spin_lock_irqsave+0x19/0xa9 (add_preempt_count+0xe/0x77 ) bash-10653 1d..4 36us : sched_switch_callback+0x73/0x81 (schedule+0x483/0x6d5 ) vim:ft=help ============ The [...] was added here to not waste your email box space. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- include/linux/ftrace.h | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) (limited to 'include') diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index b96ef14c249..db8a5e7abe4 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -5,10 +5,6 @@ #include -#define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0)) -#define CALLER_ADDR1 ((unsigned long)__builtin_return_address(1)) -#define CALLER_ADDR2 ((unsigned long)__builtin_return_address(2)) - typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip); struct ftrace_ops { @@ -35,4 +31,23 @@ extern void mcount(void); # define unregister_ftrace_function(ops) do { } while (0) # define clear_ftrace_function(ops) do { } while (0) #endif /* CONFIG_FTRACE */ + + +#ifdef CONFIG_FRAME_POINTER +/* TODO: need to fix this for ARM */ +# define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0)) +# define CALLER_ADDR1 ((unsigned long)__builtin_return_address(1)) +# define CALLER_ADDR2 ((unsigned long)__builtin_return_address(2)) +# define CALLER_ADDR3 ((unsigned long)__builtin_return_address(3)) +# define CALLER_ADDR4 ((unsigned long)__builtin_return_address(4)) +# define CALLER_ADDR5 ((unsigned long)__builtin_return_address(5)) +#else +# define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0)) +# define CALLER_ADDR1 0UL +# define CALLER_ADDR2 0UL +# define CALLER_ADDR3 0UL +# define CALLER_ADDR4 0UL +# define CALLER_ADDR5 0UL +#endif + #endif /* _LINUX_FTRACE_H */ -- cgit v1.2.3-70-g09d2