* [PATCH] tasklet: Introduce tasklet tracepoints
@ 2020-09-05 6:04 Muchun Song
2020-09-18 16:46 ` Steven Rostedt
2020-09-24 17:59 ` Thomas Gleixner
0 siblings, 2 replies; 5+ messages in thread
From: Muchun Song @ 2020-09-05 6:04 UTC (permalink / raw)
To: rostedt, mingo, tglx, peterz, will, romain.perier
Cc: linux-kernel, Muchun Song
Introduce tracepoints for tasklets just like softirq does. In this case,
we can calculate tasklet latency and know what tasklet run.
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
---
include/trace/events/irq.h | 44 ++++++++++++++++++++++++++++++++++++++
kernel/softirq.c | 2 ++
2 files changed, 46 insertions(+)
diff --git a/include/trace/events/irq.h b/include/trace/events/irq.h
index eeceafaaea4c..69a16f3a21c2 100644
--- a/include/trace/events/irq.h
+++ b/include/trace/events/irq.h
@@ -160,6 +160,50 @@ DEFINE_EVENT(softirq, softirq_raise,
TP_ARGS(vec_nr)
);
+DECLARE_EVENT_CLASS(tasklet,
+
+ TP_PROTO(struct tasklet_struct *t),
+
+ TP_ARGS(t),
+
+ TP_STRUCT__entry(
+ __field( void *, callback )
+ ),
+
+ TP_fast_assign(
+ __entry->callback = t->callback;
+ ),
+
+ TP_printk("callback=%ps", __entry->callback)
+);
+
+/**
+ * tasklet_entry - called immediately before the tasklet handler
+ * @t: pointer to struct tasklet_struct
+ *
+ * When used in combination with the tasklet_exit tracepoint
+ * we can determine the tasklet handler routine.
+ */
+DEFINE_EVENT(tasklet, tasklet_entry,
+
+ TP_PROTO(struct tasklet_struct *t),
+
+ TP_ARGS(t)
+);
+
+/**
+ * tasklet_exit - called immediately after the tasklet handler returns
+ * @t: pointer to struct tasklet_struct
+ *
+ * When used in combination with the tasklet_entry tracepoint
+ * we can determine the tasklet handler routine.
+ */
+DEFINE_EVENT(tasklet, tasklet_exit,
+
+ TP_PROTO(struct tasklet_struct *t),
+
+ TP_ARGS(t)
+);
#endif /* _TRACE_IRQ_H */
/* This part must be outside protection */
diff --git a/kernel/softirq.c b/kernel/softirq.c
index bf88d7f62433..0f9f5b2cc3d3 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -553,10 +553,12 @@ static void tasklet_action_common(struct softirq_action *a,
if (!test_and_clear_bit(TASKLET_STATE_SCHED,
&t->state))
BUG();
+ trace_tasklet_entry(t);
if (t->use_callback)
t->callback(t);
else
t->func(t->data);
+ trace_tasklet_exit(t);
tasklet_unlock(t);
continue;
}
--
2.20.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] tasklet: Introduce tasklet tracepoints
2020-09-05 6:04 [PATCH] tasklet: Introduce tasklet tracepoints Muchun Song
@ 2020-09-18 16:46 ` Steven Rostedt
2020-09-19 4:04 ` [External] " Muchun Song
2020-09-24 17:59 ` Thomas Gleixner
1 sibling, 1 reply; 5+ messages in thread
From: Steven Rostedt @ 2020-09-18 16:46 UTC (permalink / raw)
To: Muchun Song; +Cc: mingo, tglx, peterz, will, romain.perier, linux-kernel
On Sat, 5 Sep 2020 14:04:12 +0800
Muchun Song <songmuchun@bytedance.com> wrote:
> Introduce tracepoints for tasklets just like softirq does. In this case,
> we can calculate tasklet latency and know what tasklet run.
>
> Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> ---
> include/trace/events/irq.h | 44 ++++++++++++++++++++++++++++++++++++++
> kernel/softirq.c | 2 ++
> 2 files changed, 46 insertions(+)
>
> diff --git a/include/trace/events/irq.h b/include/trace/events/irq.h
> index eeceafaaea4c..69a16f3a21c2 100644
> --- a/include/trace/events/irq.h
> +++ b/include/trace/events/irq.h
> @@ -160,6 +160,50 @@ DEFINE_EVENT(softirq, softirq_raise,
> TP_ARGS(vec_nr)
> );
>
> +DECLARE_EVENT_CLASS(tasklet,
> +
> + TP_PROTO(struct tasklet_struct *t),
> +
> + TP_ARGS(t),
> +
> + TP_STRUCT__entry(
> + __field( void *, callback )
> + ),
> +
> + TP_fast_assign(
> + __entry->callback = t->callback;
I think you need to replicate the logic in the code:
if (t->use_callback)
__entry->callback = t->callback;
else
__entry->callback = t->func;
-- Steve
> + ),
> +
> + TP_printk("callback=%ps", __entry->callback)
> +);
> +
> +/**
> + * tasklet_entry - called immediately before the tasklet handler
> + * @t: pointer to struct tasklet_struct
> + *
> + * When used in combination with the tasklet_exit tracepoint
> + * we can determine the tasklet handler routine.
> + */
> +DEFINE_EVENT(tasklet, tasklet_entry,
> +
> + TP_PROTO(struct tasklet_struct *t),
> +
> + TP_ARGS(t)
> +);
> +
> +/**
> + * tasklet_exit - called immediately after the tasklet handler returns
> + * @t: pointer to struct tasklet_struct
> + *
> + * When used in combination with the tasklet_entry tracepoint
> + * we can determine the tasklet handler routine.
> + */
> +DEFINE_EVENT(tasklet, tasklet_exit,
> +
> + TP_PROTO(struct tasklet_struct *t),
> +
> + TP_ARGS(t)
> +);
> #endif /* _TRACE_IRQ_H */
>
> /* This part must be outside protection */
> diff --git a/kernel/softirq.c b/kernel/softirq.c
> index bf88d7f62433..0f9f5b2cc3d3 100644
> --- a/kernel/softirq.c
> +++ b/kernel/softirq.c
> @@ -553,10 +553,12 @@ static void tasklet_action_common(struct softirq_action *a,
> if (!test_and_clear_bit(TASKLET_STATE_SCHED,
> &t->state))
> BUG();
> + trace_tasklet_entry(t);
> if (t->use_callback)
> t->callback(t);
> else
> t->func(t->data);
> + trace_tasklet_exit(t);
> tasklet_unlock(t);
> continue;
> }
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [External] Re: [PATCH] tasklet: Introduce tasklet tracepoints
2020-09-18 16:46 ` Steven Rostedt
@ 2020-09-19 4:04 ` Muchun Song
0 siblings, 0 replies; 5+ messages in thread
From: Muchun Song @ 2020-09-19 4:04 UTC (permalink / raw)
To: Steven Rostedt
Cc: Ingo Molnar, Thomas Gleixner, Peter Zijlstra, Will Deacon,
romain.perier, LKML
On Sat, Sep 19, 2020 at 12:46 AM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Sat, 5 Sep 2020 14:04:12 +0800
> Muchun Song <songmuchun@bytedance.com> wrote:
>
> > Introduce tracepoints for tasklets just like softirq does. In this case,
> > we can calculate tasklet latency and know what tasklet run.
> >
> > Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> > ---
> > include/trace/events/irq.h | 44 ++++++++++++++++++++++++++++++++++++++
> > kernel/softirq.c | 2 ++
> > 2 files changed, 46 insertions(+)
> >
> > diff --git a/include/trace/events/irq.h b/include/trace/events/irq.h
> > index eeceafaaea4c..69a16f3a21c2 100644
> > --- a/include/trace/events/irq.h
> > +++ b/include/trace/events/irq.h
> > @@ -160,6 +160,50 @@ DEFINE_EVENT(softirq, softirq_raise,
> > TP_ARGS(vec_nr)
> > );
> >
> > +DECLARE_EVENT_CLASS(tasklet,
> > +
> > + TP_PROTO(struct tasklet_struct *t),
> > +
> > + TP_ARGS(t),
> > +
> > + TP_STRUCT__entry(
> > + __field( void *, callback )
> > + ),
> > +
> > + TP_fast_assign(
> > + __entry->callback = t->callback;
>
> I think you need to replicate the logic in the code:
>
> if (t->use_callback)
> __entry->callback = t->callback;
> else
> __entry->callback = t->func;
The `callback` and `func` is union and `callback` will replace
`func` someday in the feature. So I think that here we use
`t->callback` is enough. Right? Thanks.
>
> -- Steve
>
> > + ),
> > +
> > + TP_printk("callback=%ps", __entry->callback)
> > +);
> > +
> > +/**
> > + * tasklet_entry - called immediately before the tasklet handler
> > + * @t: pointer to struct tasklet_struct
> > + *
> > + * When used in combination with the tasklet_exit tracepoint
> > + * we can determine the tasklet handler routine.
> > + */
> > +DEFINE_EVENT(tasklet, tasklet_entry,
> > +
> > + TP_PROTO(struct tasklet_struct *t),
> > +
> > + TP_ARGS(t)
> > +);
> > +
> > +/**
> > + * tasklet_exit - called immediately after the tasklet handler returns
> > + * @t: pointer to struct tasklet_struct
> > + *
> > + * When used in combination with the tasklet_entry tracepoint
> > + * we can determine the tasklet handler routine.
> > + */
> > +DEFINE_EVENT(tasklet, tasklet_exit,
> > +
> > + TP_PROTO(struct tasklet_struct *t),
> > +
> > + TP_ARGS(t)
> > +);
> > #endif /* _TRACE_IRQ_H */
> >
> > /* This part must be outside protection */
> > diff --git a/kernel/softirq.c b/kernel/softirq.c
> > index bf88d7f62433..0f9f5b2cc3d3 100644
> > --- a/kernel/softirq.c
> > +++ b/kernel/softirq.c
> > @@ -553,10 +553,12 @@ static void tasklet_action_common(struct softirq_action *a,
> > if (!test_and_clear_bit(TASKLET_STATE_SCHED,
> > &t->state))
> > BUG();
> > + trace_tasklet_entry(t);
> > if (t->use_callback)
> > t->callback(t);
> > else
> > t->func(t->data);
> > + trace_tasklet_exit(t);
> > tasklet_unlock(t);
> > continue;
> > }
>
--
Yours,
Muchun
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] tasklet: Introduce tasklet tracepoints
2020-09-05 6:04 [PATCH] tasklet: Introduce tasklet tracepoints Muchun Song
2020-09-18 16:46 ` Steven Rostedt
@ 2020-09-24 17:59 ` Thomas Gleixner
2020-09-25 2:47 ` [External] " Muchun Song
1 sibling, 1 reply; 5+ messages in thread
From: Thomas Gleixner @ 2020-09-24 17:59 UTC (permalink / raw)
To: Muchun Song, rostedt, mingo, peterz, will, romain.perier
Cc: linux-kernel, Muchun Song
On Sat, Sep 05 2020 at 14:04, Muchun Song wrote:
> Introduce tracepoints for tasklets just like softirq does.
What does softirq?
> In this case, we can calculate tasklet latency and know what tasklet
> run.
I rather see people working on removal of tasklets.
Thanks,
tglx
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [External] Re: [PATCH] tasklet: Introduce tasklet tracepoints
2020-09-24 17:59 ` Thomas Gleixner
@ 2020-09-25 2:47 ` Muchun Song
0 siblings, 0 replies; 5+ messages in thread
From: Muchun Song @ 2020-09-25 2:47 UTC (permalink / raw)
To: Thomas Gleixner
Cc: Steven Rostedt, Ingo Molnar, Peter Zijlstra, Will Deacon,
romain.perier, LKML
On Fri, Sep 25, 2020 at 1:59 AM Thomas Gleixner <tglx@linutronix.de> wrote:
>
> On Sat, Sep 05 2020 at 14:04, Muchun Song wrote:
>
> > Introduce tracepoints for tasklets just like softirq does.
>
> What does softirq?
I mean that the softirq has tracepoints and the tasklet may
also be needed.
>
> > In this case, we can calculate tasklet latency and know what tasklet
> > run.
>
> I rather see people working on removal of tasklets.
I do not know about this, why do we remove the tasklet?
>
> Thanks,
>
> tglx
Thanks.
--
Yours,
Muchun
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2020-09-25 2:48 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-09-05 6:04 [PATCH] tasklet: Introduce tasklet tracepoints Muchun Song
2020-09-18 16:46 ` Steven Rostedt
2020-09-19 4:04 ` [External] " Muchun Song
2020-09-24 17:59 ` Thomas Gleixner
2020-09-25 2:47 ` [External] " Muchun Song
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