Date:   Mon, 9 Oct 2017 16:17:31 +1100
From:   Dave Chinner <david@...morbit.com>
To:     Josef Bacik <josef@...icpanda.com>
Cc:     linux-fsdevel@...r.kernel.org, kernel-team@...com,
        linux-btrfs@...r.kernel.org, linux-block@...r.kernel.org,
        linux-ext4@...r.kernel.org, linux-xfs@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [ANNOUNCE] fsperf: a simple fs/block performance testing
 framework

On Sun, Oct 08, 2017 at 10:25:10PM -0400, Josef Bacik wrote:
> On Mon, Oct 09, 2017 at 11:51:37AM +1100, Dave Chinner wrote:
> > On Fri, Oct 06, 2017 at 05:09:57PM -0400, Josef Bacik wrote:
> > > Hello,
> > > 
> > > One thing that comes up a lot every LSF is the fact that we have no general way
> > > that we do performance testing.  Every fs developer has a set of scripts or
> > > things that they run with varying degrees of consistency, but nothing central
> > > that we all use.  I for one am getting tired of finding regressions when we are
> > > deploying new kernels internally, so I wired this thing up to try and address
> > > this need.
> > > 
> > > We all hate convoluted setups, the more brain power we have to put in to setting
> > > something up the less likely we are to use it, so I took the xfstests approach
> > > of making it relatively simple to get running and relatively easy to add new
> > > tests.  For right now the only thing this framework does is run fio scripts.  I
> > > chose fio because it already gathers loads of performance data about it's runs.
> > > We have everything we need there, latency, bandwidth, cpu time, and all broken
> > > down by reads, writes, and trims.  I figure most of us are familiar enough with
> > > fio and how it works to make it relatively easy to add new tests to the
> > > framework.
> > > 
> > > I've posted my code up on github, you can get it here
> > > 
> > > https://github.com/josefbacik/fsperf
> > > 
> > > All (well most) of the results from fio are stored in a local sqlite database.
> > > Right now the comparison stuff is very crude, it simply checks against the
> > > previous run and it only checks a few of the keys by default.  You can check
> > > latency if you want, but while writing this stuff up it seemed that latency was
> > > too variable from run to run to be useful in a "did my thing regress or improve"
> > > sort of way.
> > > 
> > > The configuration is brain dead simple, the README has examples.  All you need
> > > to do is make your local.cfg, run ./setup and then run ./fsperf and you are good
> > > to go.
> > 
> > Why re-invent the test infrastructure? Why not just make it a
> > tests/perf subdir in fstests?
> > 
> 
> Probably should have led with that shouldn't I have?  There's nothing keeping me
> from doing it, but I didn't want to try and shoehorn in a python thing into
> fstests.  I need python to do the sqlite and the json parsing to dump into the
> sqlite database.
> 
> Now if you (and others) are not opposed to this being dropped into tests/perf
> then I'll work that up.  But it's definitely going to need to be done in python.
> I know you yourself have said you aren't opposed to using python in the past, so
> if that's still the case then I can definitely wire it all up.

I have no problems with people using python for stuff like this but,
OTOH, I'm not the fstests maintainer anymore :P

> > > The plan is to add lots of workloads as we discover regressions and such.  We
> > > don't want anything that takes too long to run otherwise people won't run this,
> > > so the existing tests don't take much longer than a few minutes each.  I will be
> > > adding some more comparison options so you can compare against averages of all
> > > previous runs and such.
> > 
> > Yup, that fits exactly into what fstests is for... :P
> > 
> > Integrating into fstests means it will be immediately available to
> > all fs developers, it'll run on everything that everyone already has
> > setup for filesystem testing, and it will have familiar mkfs/mount
> > option setup behaviour so there's no new hoops for everyone to jump
> > through to run it...
> > 
> 
> TBF I specifically made it as easy as possible because I know we all hate trying
> to learn new shit.

Yeah, it's also hard to get people to change their workflows to add
a whole new test harness into them. It's easy if it's just a new
command to an existing workflow :P

> I figured this was different enough to warrant a separate
> project, especially since I'm going to add block device jobs so Jens can test
> block layer things.  If we all agree we'd rather see this in fstests then I'm
> happy to do that too.  Thanks,

I'm not fussed either way - it's a good discussion to have, though.

If I want to add tests (e.g. my time-honoured fsmark tests), where
should I send patches?

Cheers,

Dave.
-- 
Dave Chinner
david@...morbit.com

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