Hey, I just want to close the loop here. Last week up until now I've successfully run several hundred jobs and not a single skewed output has come across. Is this patch integrated into the main code base or the latest release? Regards Michael On Mon, Nov 10, 2014 at 7:33 AM, Jens Axboe <axboe@xxxxxxxxx> wrote: > On 2014-11-10 07:19, Vasily Tarasov wrote: >> >> Hi Jens, >> >> td->start is used in __show_running_run_stats() to compute the time >> that passed since the beginning of the loop (stored in td->start) to >> the moment when periodical statistics need to be printed. Then >> td->ts.runtime[] is temporarily updated based on the computed value. >> >> In thread_main(), similar actions are taken to update td->ts.runtime[] >> based on the td->start and the loop's elapsed time. Without the patch, >> td->start is set in the very beginning of the loop in thread_main(). >> So, it leaves a time window between the end of the current loop and >> the beginning of the next loop when td->ts.runtime[] is already >> updated while td->start still stores the start of the previous lop. If >> __show_running_run_stats() is called during that window - the time can >> be (temporarily) added twice to td->ts.runtime[]. >> >> However, if we reset the start time in the end of the loop under the >> stat_mutex it should not happen. >> >> I would agree that having a per-td mutex might be an overkill >> considering that people usually print statistics periodically with >> relatively long intervals: 1, 5, 10, 60 seconds. > > > Thanks, I missed the change in addition after IO was done, hence the > question on ->start. I did commit the patch as-is yesterday, thanks! > > -- > Jens Axboe > -- To unsubscribe from this list: send the line "unsubscribe fio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
