----- On Jul 5, 2016, at 11:19 AM, rostedt rost...@goodmis.org wrote:
> On Mon, 4 Jul 2016 15:46:04 -0400
> Julien Desfossez <jdesfos...@efficios.com> wrote:
>
>
>> diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
>> index 9b90c57..fcb0f29 100644
>> --- a/include/trace/events/sched.h
>> +++ b/include/trace/events/sched.h
>> @@ -8,6 +8,34 @@
>> #include <linux/tracepoint.h>
>> #include <linux/binfmts.h>
>>
>> +#define SCHEDULING_POLICY \
>> + EM( SCHED_NORMAL, "SCHED_NORMAL") \
>> + EM( SCHED_FIFO, "SCHED_FIFO") \
>> + EM( SCHED_RR, "SCHED_RR") \
>> + EM( SCHED_BATCH, "SCHED_BATCH") \
>> + EM( SCHED_IDLE, "SCHED_IDLE") \
>> + EMe(SCHED_DEADLINE, "SCHED_DEADLINE")
>> +
>> +/*
>> + * First define the enums in the above macros to be exported to userspace
>> + * via TRACE_DEFINE_ENUM().
>> + */
>> +#undef EM
>> +#undef EMe
>> +#define EM(a, b) TRACE_DEFINE_ENUM(a);
>> +#define EMe(a, b) TRACE_DEFINE_ENUM(a);
>> +
>> +SCHEDULING_POLICY
>> +
>> +/*
>> + * Now redefine the EM() and EMe() macros to map the enums to the strings
>> + * that will be printed in the output.
>> + */
>> +#undef EM
>> +#undef EMe
>> +#define EM(a, b) {a, b},
>> +#define EMe(a, b) {a, b}
>> +
>> /*
>> * Tracepoint for calling kthread_stop, performed to end a kthread:
>> */
>> @@ -562,6 +590,46 @@ TRACE_EVENT(sched_wake_idle_without_ipi,
>>
>> TP_printk("cpu=%d", __entry->cpu)
>> );
>> +
>> +/*
>> + * Tracepoint for showing scheduling priority changes.
>> + */
>> +TRACE_EVENT(sched_prio_update,
>
> I'm fine with the addition of this tracepoint. You'll have to get by
> Peter Zijlstra for it.
Great!
>
>> +
>> + TP_PROTO(struct task_struct *tsk),
>> +
>> + TP_ARGS(tsk),
>> +
>> + TP_STRUCT__entry(
>> + __array( char, comm, TASK_COMM_LEN )
>
> I could imagine this being a high frequency tracepoint, especially with
> a lot of boosting going on. Can we nuke the comm recording and let the
> userspace tools just hook to the sched_switch tracepoint for that?
We can surely do that.
Just to clarify: currently this tracepoint is *not* hooked on PI boosting,
as described in the changelog. This tracepoint is about the prio attributes
set by user-space. The PI boosting temporarily changes the task struct prio
without updating the associated policy, which seems rather
implementation-specific and odd to expose.
Thoughts ?
Thanks,
Mathieu
>
> -- Steve
>
>
>> + __field( pid_t, pid )
>> + __field( unsigned int, policy )
>> + __field( int, nice )
>> + __field( unsigned int, rt_priority )
>> + __field( u64, dl_runtime )
>> + __field( u64, dl_deadline )
>> + __field( u64, dl_period )
>> + ),
>> +
>> + TP_fast_assign(
>> + memcpy(__entry->comm, tsk->comm, TASK_COMM_LEN);
>> + __entry->pid = tsk->pid;
>> + __entry->policy = tsk->policy;
>> + __entry->nice = task_nice(tsk);
>> + __entry->rt_priority = tsk->rt_priority;
>> + __entry->dl_runtime = tsk->dl.dl_runtime;
>> + __entry->dl_deadline = tsk->dl.dl_deadline;
>> + __entry->dl_period = tsk->dl.dl_period;
>> + ),
>> +
>> + TP_printk("comm=%s pid=%d, policy=%s, nice=%d, rt_priority=%u, "
>> + "dl_runtime=%Lu, dl_deadline=%Lu, dl_period=%Lu",
>> + __entry->comm, __entry->pid,
>> + __print_symbolic(__entry->policy, SCHEDULING_POLICY),
>> + __entry->nice, __entry->rt_priority,
>> + __entry->dl_runtime, __entry->dl_deadline,
>> + __entry->dl_period)
>> +);
>> #endif /* _TRACE_SCHED_H */
>>
>> /* This part must be outside protection */
>> diff --git a/kernel/fork.c b/kernel/fork.c
>> index 7926993..ac4294a 100644
>> --- a/kernel/fork.c
>> +++ b/kernel/fork.c
>> @@ -1773,6 +1773,7 @@ long _do_fork(unsigned long clone_flags,
>> struct pid *pid;
>>
>> trace_sched_process_fork(current, p);
>> + trace_sched_prio_update(p);
>>
>> pid = get_task_pid(p, PIDTYPE_PID);
>> nr = pid_vnr(pid);
>> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
>> index ce83e39..c729425 100644
>> --- a/kernel/sched/core.c
>> +++ b/kernel/sched/core.c
>> @@ -3708,6 +3708,7 @@ void set_user_nice(struct task_struct *p, long nice)
>> resched_curr(rq);
>> }
>> out_unlock:
>> + trace_sched_prio_update(p);
>> task_rq_unlock(rq, p, &rf);
>> }
>> EXPORT_SYMBOL(set_user_nice);
>> @@ -3912,6 +3913,8 @@ static void __setscheduler(struct rq *rq, struct
>> task_struct *p,
>> p->sched_class = &rt_sched_class;
>> else
>> p->sched_class = &fair_sched_class;
>> +
>> + trace_sched_prio_update(p);
>> }
>>
> > static void
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
