On Tue, 3 Dec 2024 16:48:48 +0800 (CST) <jiang.kun2@xxxxxxxxxx> wrote: > From: Wang Yaxin <wang.yaxin@xxxxxxxxxx> > > Introduce the use cases of delay max, which can help quickly detect > potential abnormal delays in the system and record the types and > specific details of delay spikes. > > Problem > ======== > Delay accounting can track the average delay of processes to show > system workload. However, when a process experiences a significant > delay, maybe a delay spike, which adversely affects performance, > getdelays can only display the average system delay over a period > of time. Yet, average delay is unhelpful for diagnosing delay peak. > It is not even possible to determine which type of delay has spiked, > as this information might be masked by the average delay. > > Solution > ========= > the 'delay max' can display delay peak since the system's startup, > which can record potential abnormal delays over time, including > the type of delay and the maximum delay. This is helpful for > quickly identifying crash caused by delay. Seems sensible, and the implementation is straightforward. I'll queue it for testing and review. > include/linux/delayacct.h | 7 ++++ > include/linux/sched.h | 3 ++ > include/uapi/linux/taskstats.h | 9 ++++++ > kernel/delayacct.c | 35 ++++++++++++++------ > kernel/sched/stats.h | 5 ++- > tools/accounting/getdelays.c | 59 ++++++++++++++++++++-------------- Please prepare a v2 which includes an update to Documentation/accounting/delay-accounting.rst. > > ... > > --- a/kernel/delayacct.c > +++ b/kernel/delayacct.c > @@ -95,7 +95,7 @@ void __delayacct_tsk_init(struct task_struct *tsk) > * Finish delay accounting for a statistic using its timestamps (@start), > * accumalator (@total) and @count And I wouldn't be offended if v2 fixed that spelling error! "accumulator".
