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author | Arjan van de Ven <arjan@linux.intel.com> | 2010-08-21 13:07:26 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-08-21 13:19:37 -0700 |
commit | e36c886a0f9d624377977fa6cae309cfd7f362fa (patch) | |
tree | f75e7c3e50a48c671ed4dff33103f601a2204af9 | |
parent | 69b26c7ad00fd5b6129400725e2ffb95134a0e1b (diff) | |
download | linux-3.10-e36c886a0f9d624377977fa6cae309cfd7f362fa.tar.gz linux-3.10-e36c886a0f9d624377977fa6cae309cfd7f362fa.tar.bz2 linux-3.10-e36c886a0f9d624377977fa6cae309cfd7f362fa.zip |
workqueue: Add basic tracepoints to track workqueue execution
With the introduction of the new unified work queue thread pools,
we lost one feature: It's no longer possible to know which worker
is causing the CPU to wake out of idle. The result is that PowerTOP
now reports a lot of "kworker/a:b" instead of more readable results.
This patch adds a pair of tracepoints to the new workqueue code,
similar in style to the timer/hrtimer tracepoints.
With this pair of tracepoints, the next PowerTOP can correctly
report which work item caused the wakeup (and how long it took):
Interrupt (43) i915 time 3.51ms wakeups 141
Work ieee80211_iface_work time 0.81ms wakeups 29
Work do_dbs_timer time 0.55ms wakeups 24
Process Xorg time 21.36ms wakeups 4
Timer sched_rt_period_timer time 0.01ms wakeups 1
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | include/trace/events/workqueue.h | 62 | ||||
-rw-r--r-- | kernel/workqueue.c | 9 |
2 files changed, 71 insertions, 0 deletions
diff --git a/include/trace/events/workqueue.h b/include/trace/events/workqueue.h new file mode 100644 index 00000000000..49682d7e9d6 --- /dev/null +++ b/include/trace/events/workqueue.h @@ -0,0 +1,62 @@ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM workqueue + +#if !defined(_TRACE_WORKQUEUE_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_WORKQUEUE_H + +#include <linux/tracepoint.h> +#include <linux/workqueue.h> + +/** + * workqueue_execute_start - called immediately before the workqueue callback + * @work: pointer to struct work_struct + * + * Allows to track workqueue execution. + */ +TRACE_EVENT(workqueue_execute_start, + + TP_PROTO(struct work_struct *work), + + TP_ARGS(work), + + TP_STRUCT__entry( + __field( void *, work ) + __field( void *, function) + ), + + TP_fast_assign( + __entry->work = work; + __entry->function = work->func; + ), + + TP_printk("work struct %p: function %pf", __entry->work, __entry->function) +); + +/** + * workqueue_execute_end - called immediately before the workqueue callback + * @work: pointer to struct work_struct + * + * Allows to track workqueue execution. + */ +TRACE_EVENT(workqueue_execute_end, + + TP_PROTO(struct work_struct *work), + + TP_ARGS(work), + + TP_STRUCT__entry( + __field( void *, work ) + ), + + TP_fast_assign( + __entry->work = work; + ), + + TP_printk("work struct %p", __entry->work) +); + + +#endif /* _TRACE_WORKQUEUE_H */ + +/* This part must be outside protection */ +#include <trace/define_trace.h> diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 2994a0e3a61..8bd600c020e 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -35,6 +35,9 @@ #include <linux/lockdep.h> #include <linux/idr.h> +#define CREATE_TRACE_POINTS +#include <trace/events/workqueue.h> + #include "workqueue_sched.h" enum { @@ -1790,7 +1793,13 @@ static void process_one_work(struct worker *worker, struct work_struct *work) work_clear_pending(work); lock_map_acquire(&cwq->wq->lockdep_map); lock_map_acquire(&lockdep_map); + trace_workqueue_execute_start(work); f(work); + /* + * While we must be careful to not use "work" after this, the trace + * point will only record its address. + */ + trace_workqueue_execute_end(work); lock_map_release(&lockdep_map); lock_map_release(&cwq->wq->lockdep_map); |