On Wed, Sep 02, 2020 at 10:35:34PM +0000, gengdongjiu wrote: > > NAK, that tracepoint is already broken, we don't want to proliferate the > > broken. > > Sorry, What the meaning that tracepoint is already broken?
Just that, the tracepoint is crap. But we can't fix it because ABI. Did I tell you I utterly hate tracepoints? > Maybe I need to explain the reason that why I add two trace point. > when using perf tool or Ftrace sysfs to capture the task wake-up latency and > the task leaving running queue time, usually the trace data is too large and > the CPU utilization rate is too high in the process due to a lot of disk > write. Sometimes even the disk is full, the issue still does not reproduced > that above two time exceed a certain threshold. So I added two trace points, > using filter we can only record the abnormal trace that includes wakeup > latency and leaving running time larger than an threshold. > Or do you have better solution? Learn to use a MUA and wrap your lines at 78 chars like normal people. Yes, use ftrace synthetic events, or bpf or really anything other than this. > > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c index > > > 8471a0f7eb32..b5a1928dc948 100644 > > > --- a/kernel/sched/core.c > > > +++ b/kernel/sched/core.c > > > @@ -2464,6 +2464,8 @@ static void ttwu_do_wakeup(struct rq *rq, struct > > > task_struct *p, int wake_flags, { > > > check_preempt_curr(rq, p, wake_flags); > > > p->state = TASK_RUNNING; > > > + p->ts_wakeup = local_clock(); > > > + p->wakeup_state = true; > > > trace_sched_wakeup(p); > > > > > > #ifdef CONFIG_SMP > > > > NAK, userless overhead. > > When sched switch, we do not know the next task previous state and > wakeup timestamp, so I record the task previous state if it is waken > from sleep. And then it can calculate the wakeup latency when task > switch. I don't care. You're making things slower.