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
