Re: A quick fio test (was Re: [patch 00/13] Syslets, "Threadlets", generic AIO support, v3)

Suparna Bhattacharya
2007-02-23T17:10:18Z

On Fri, Feb 23, 2007 at 05:25:08PM +0100, Jens Axboe wrote:
> On Fri, Feb 23 2007, Suparna Bhattacharya wrote:
> > On Fri, Feb 23, 2007 at 03:58:26PM +0100, Ingo Molnar wrote:
> > >
> > > * Suparna Bhattacharya <suparna@in.ibm.com> wrote:
> > >
> > > > As a really crude (and not very realistic) example of the potential
> > > > impact of large numbers of outstanding IOs, I tried some quick direct
> > > > IO comparisons using fio:
> > > >
> > > > [global]
> > > > ioengine=syslet-rw
> > > > buffered=0
> > > > rw=randread
> > > > bs=64k
> > > > size=1024m
> > > > iodepth=64
> > >
> > > could you please try those iodepth=20000 tests with the latest
> > > fio-testing branch of fio as well? Jens wrote a new, smarter syslet
> > > plugin for FIO. You'll need the v3 syslet kernel plus:
> > >
> > > git-clone git://git.kernel.dk/data/git/fio.git
> > > cd fio
> > > git-checkout syslet-testing
> > >
> > > my expectation is that it should behave better with iodepth=20000
> > > (although i havent tried that yet).
> >
> > I picked up the fio snapshot from 22nd Feb (fio-git-20070222212513.tar.gz)
> > and used the v3 syslet patches from your web-site.
> >
> > Do I still need to get something more recent ?
>
> Yes, you need to test the syslet+testing branch that Ingo referenced.
> Your test above is not totally fair right now, since you are doing
> significantly less system calls with libaio. So to compare apples with
> apples, try the syslet-testing branch. If you can't get it because of
> firewall problems, check http://brick.kernel.dk/snaps/ for the latest
> fio snapshot. If it has the syslet-testing branch, then that is
> recent enough.

I have a feeling this is getting to be a little more bleeding edge than
I had anticipated :), so will just hold off for a bit until this
crystallizes a bit.

Regards
Suparna

>
> --
> Jens Axboe

--
Suparna Bhattacharya (suparna@in.ibm.com)
Linux Technology Center
IBM Software Lab, India