On 09/14/2017 10:45 AM, Jiang, Dave wrote: > > >> -----Original Message----- >> From: Jens Axboe [mailto:axboe@xxxxxxxxx] >> Sent: Wednesday, September 13, 2017 9:09 PM >> To: Jiang, Dave <dave.jiang@xxxxxxxxx> >> Cc: fio@xxxxxxxxxxxxxxx; Williams, Dan J <dan.j.williams@xxxxxxxxx> >> Subject: Re: fio and total latency percentile >> >> On 09/13/2017 10:03 PM, Jens Axboe wrote: >>> On 09/13/2017 04:59 PM, Jens Axboe wrote: >>>> On 09/07/2017 01:59 PM, Dave Jiang wrote: >>>>> Jens, >>>>> fio can display completion latency percentages via the percentile_list >>>>> parameter. I can get p90 and p99 numbers for clat via >>>>> percentile_list=90:99. Is there a way to get the overall latency for >>>>> percentile? I'm interested in the total latency measurements for p90 and >>>>> p99 while doing some measurements on the persistent memory block driver >>>>> and playing around using DMA engines for transfer. >>>> >>>> If I understand correctly, you are using an IO engine that is async, and >>>> you want the latency percentiles to reflect total IO time >>>> (submission+completion), not just completion time? >>>> >>>> We can't currently do that, but it'd be trivial to do with an option of >>>> some sort. Currently the percentile enable option is clat_percentile, >>>> and it defaults to on. We could have a lat_percentile option that, if >>>> enabled, would change the reporting to being total IO time. IOW: >>>> >>>> clat_percentile=1 Latency percentiles are completion latencies >>>> lat_percentile=1 Latency percentiles are total IO time >>>> >>>> and have them be mutually exclusive. >>> >>> Something like the below. Please try it out and see if it works for you. >> >> Or just try current -git. I got cocky and just committed it. > > Works great! Exactly what I need. Thanks Jens! Good to hear! Thanks for testing. -- 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
