log_hist_coarseness parameter causes fio-hist-log-pctiles.py to fail

[bengland2]

For example, if log_hist_coarseness=4 parameter is used in a job file, the resulting log causes this error.

[bengland@bene-laptop repro]$ python ../fio-histo-log-pctiles.py x_clat_hist.1.log 
fio version = 3
bucket groups = 29
bucket bits = 6
time quantum = 1 sec
percentiles = 0.0,50.0,95.0,99.0,100.0
buckets per group = 64
buckets per interval = 1856 
output unit = usec
ERROR: 116 buckets per interval but 1856 expected in in histogram record 2 file x_clat_hist.1.log

Seems like it could automatically recognize the coarseness from the number of buckets in the record, since bucket count is 1856/(2^k) where k is coarseness.

[bengland2]

@sitsofe Do you have a preference about which of the 3 issues is most important to deal with first? My vote would be issue 827, then issue 826 (this one), then then issue 828.

[sitsofe]

@bengland2 I concur - #827, #826, #828.

[sitsofe]

(BTW working out the bucket count reminds me of https://www.spinics.net/lists/fio/msg06934.html )

[bengland2]

now it looks like 827 has been solved, I'll move onto this one.