From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: problem with fio --client and latency logs References: <1119349874.66202652.1464289871526.JavaMail.zimbra@redhat.com> <57485CF7.2070308@kernel.dk> From: Jens Axboe Message-ID: <57487D92.7070306@kernel.dk> Date: Fri, 27 May 2016 11:02:10 -0600 MIME-Version: 1.0 In-Reply-To: <57485CF7.2070308@kernel.dk> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit To: Ben England , fio@vger.kernel.org Cc: Tim Wilkinson , Andrew Theurer , John Harrigan List-ID: On 05/27/2016 08:43 AM, Jens Axboe wrote: > On 05/26/2016 01:11 PM, Ben England wrote: >> 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 >> Date: Thu Dec 17 14:54:15 2015 -0700 >> >> client/server: transparent handling of storing compressed logs >> >> Signed-off-by: Jens Axboe >> ------ >> >> 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. > > I have a good idea what this might be, I'll take a look at it. http://git.kernel.dk/cgit/fio/commit/?id=e35fb4c43ecc5b9d35cb5d980e811d3408fc5a4e This should fix it, can you try with current -git? -- Jens Axboe