On Mon, Sep 12, 2022 at 8:10 AM Vincent Fu <vincentfu@xxxxxxxxx> wrote: > > On 9/10/22 03:05, Matthew Eaton wrote: > > Hello fio group, > > > > I'm doing some analysis on latency outliers and I read that fio can't > > report latency higher than 17.2 seconds. This seems to fall in line > > with my testing as my logs show latency outliers max out at ~17 > > seconds. Can anyone confirm if this is accurate? > > > > https://fossies.org/linux/fio/doc/fio-histo-log-pctiles.pdf > > "Note that the highest max latency for any bucket is 17.2 seconds = > > (64 * 2^28)/1000.0 ." > > ~17s is consistent with this comment in stat.h: > > https://github.com/axboe/fio/blob/master/stat.h#L48 > > 2^(29 + 6 - 1) = 2^34 = 17179869184 ns > > If you need to measure longer durations you should be able to just > increase the value for FIO_IO_U_PLAT_GROUP_NR. > > Vincent Hi Vincent, Thanks for pointing me in the right direction. I'm taking a look now.
