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From: Vincent Fu <vincentfu@gmail.com>
To: Travis Downs <travis.downs@gmail.com>, fio@vger.kernel.org
Subject: Re: Ending condition for non-rr file service
Date: Fri, 26 May 2023 13:28:28 -0400	[thread overview]
Message-ID: <09fe872b-37ac-48f3-44cc-5c17b48a7884@gmail.com> (raw)
In-Reply-To: <CAOBGo4wFOxyXXhjeqk6MJ-QkjsaypQYOBaL8wCVkMpk6H-khsw@mail.gmail.com>

On 5/26/23 11:38, Travis Downs wrote:
 > I guess I understand when fio "stops" when using 1 file per job: after
 > `io_size` IOs,
 > which is usually the same as `size` if `io_size` has not been
 > specified explicitly.
 >
 > When size == io_size, this means that all blocks of the files are
 > written exactly once
 > with linear or random writes, except if norandmap=1, in which case
 > some blocks will
 > likely be written 0 times and others 2 or more times.
 >
 > How does this work for nrfiles > 1 and linear writes (rw=write) and
 > file_service_type
 > set to one of the random ones? For the non-uniform distributions some
 > files will be
 > written at a higher rate than others: does the write pointer just loop
 > when it gets to
 > the end of the file? So io_size writes will still be done, but some
 > files will not be
 > completely written while others may be written more than once?
 >
 > Travis
Fio's behavior in this situation is not explicitly spelled out in the 
documentation.

For a job with a single file, fio will just start over again and write 
the file multiple times when io_size > filesize. I would expect the same 
to happen when nrfiles > 1.

Try a run with --debug=io,file and let us know!

Vincent

      reply	other threads:[~2023-05-26 17:28 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-26 15:38 Ending condition for non-rr file service Travis Downs
2023-05-26 17:28 ` Vincent Fu [this message]

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