recently I noticed a problem in master branch when fio --client is used. latency logs generated with it have large numbers of "0, 0, 0, 0" records at the end of the file. I have a simple reproducer fio jobfile:
--------- reproducer.fiojob ----
[global]
numjobs=1
directory=/var/tmp
[shared-files]
rw=randread
write_lat_log=1thr
ioengine=sync
bs=4k # I/O size
filesize=1g # file size
runtime=20
-------------
If you run this job file like this:
# fio --server --daemonize=/var/run/fiosvr.pid
# fio --client=localhost reproducer.fiojob
You get the latency log 1thr_clat.1.log with the 0 records at the end. If you run the same job file with:
# fio reproducer.fiojob
You don't get the 0 records. This explains why Ceph CBT does not have the problem, for example.
I bisected fio history using git until I found the first commit that failed:
-------
commit 0cba0f919ee6af7dd65df436884336cff9c903f9
Author: Jens Axboe <axboe@xxxxxx>
Date: Thu Dec 17 14:54:15 2015 -0700
client/server: transparent handling of storing compressed logs
Signed-off-by: Jens Axboe <axboe@xxxxxx>
------
I could use some help figuring out what went wrong at this point, the diffs were complicated but it seemed possible that this commit was related to my problem.
-ben england
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