Re: Measuring IOPS (solved, I think)

[Martin Steigerwald <Martin@lichtvoll.de>]

Am Mittwoch, 3. August 2011 schrieben Sie:
> On 2011-08-02 23:28, Martin Steigerwald wrote:
> > Am Dienstag, 2. August 2011 schrieben Sie:
> >> That's a long email! The stonewall should be put in the job section
> >> that has to wait for previous jobs. So, ala:
> >> 
> >> [job1]
> >> something
> >> 
> >> [job2]
> >> stonewall       # will wait for job1 to finish
> >> something
> >> 
> >> [job3]
> >> something       # will run in parallel with job2
> >> 
> >> [job4]
> >> stonewall       # will run when job2+3 are finished
> >> something
> >> 
> >> If that's not the case, something is broken. A quick test here seems
> >> to show that it works.
> > 
> > Its documented. From the manpage that I read several times by now:
> > 
> > Wait for preceding jobs in the job file to exit before starting this
> > one. stonewall implies new_group.
> > 
> > 
> > Somehow despite my reading of manpage, README, HOWTO I came to the
> > thought that it tells fio to wait for the current job to finish,
> > thus I had the stonewall options misordered.
> > 
> > I expect that it works exactly as you said and try it this way.
> > Instead of omitting the last stonewall option in my iops job file I
> > could omit the first for the first job. Cause the first job does not
> > need to wait for a previous job.
> 
> Good, that makes me feel a little better :-)

What did you feel bad about? I didn´t intend to trigger bad feelings.

There was nothing wrong with fio. Behavior was documented.

> Perhaps the name isn't that great? I'll gladly put in an alias for that
> option, "wait_for_previous" or "barrier" or something like that. Fence?

wait_before? But then "wait_for_previous" might be the clearest 
description. "wait_before" would make sense with an "wait_after" that 
waits after the job for its completion. But two options for basically the 
same thing might complicate matters even more.

So "wait_for_previous" or maybe "finish_previous_first" or just 
"finish_previous" would be fine with me.

But then this doesn´t imply that fio does a cache flush. But that could be 
documented in the manpage with an additional hint on this option. I will 
think about it and possibly provide a patch.

-- 
Martin 'Helios' Steigerwald - http://www.Lichtvoll.de
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