Messages in this thread | | | Date | Fri, 02 Nov 2007 22:05:29 +0530 | From | Balbir Singh <> | Subject | Re: [PATCH] Fix delay accounting regression |
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Ingo Molnar wrote: > * Balbir Singh <balbir@linux.vnet.ibm.com> wrote: > >> Fix the delay accounting regression introduced by commit >> 75d4ef16a6aa84f708188bada182315f80aab6fa. rq no longer has sched_info >> data associated with it. task_struct sched_info structure is used by >> delay accounting to provide back statistics to user space. > > no, this really is broken code. sched_clock() is not a generally > reliable time source so at a minimum the rq->clock fix i mentioned is > needed. What user-space tools are utilizing delay-accounting by the way?
Applications I can think of are
1. iotop 2. Some typical applications are mentioned in https://ols2006.108.redhat.com/2007/Reprints/nagar-Reprint.pdf
> We have most of this data available under SCHEDSTATS - how about > consolidating CONFIG_TASK_DELAY_ACCT into CONFIG_SCHEDSTATS? > > Ingo
Yes, we do use schedstats - except for two cases that I know of?
1. To accumulate information in taskstats to share with user space (we copy the data from schedstats into taskstats) 2. We accumulate the data for dead threads in a thread group
-- Warm Regards, Balbir Singh Linux Technology Center IBM, ISTL - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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