Date: Fri, 23 Feb 2007 17:25:08 +0100
From: Jens Axboe <jens.axboe@oracle.com>
To: Suparna Bhattacharya <suparna@in.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>, linux-kernel@vger.kernel.org,
       Linus Torvalds <torvalds@linux-foundation.org>,
       Arjan van de Ven <arjan@infradead.org>,
       Christoph Hellwig <hch@infradead.org>, Andrew Morton <akpm@zip.com.au>,
       Alan Cox <alan@lxorguk.ukuu.org.uk>,
       Ulrich Drepper <drepper@redhat.com>, Zach Brown <zach.brown@oracle.com>,
       Evgeniy Polyakov <johnpol@2ka.mipt.ru>,
       "David S. Miller" <davem@davemloft.net>,
       Davide Libenzi <davidel@xmailserver.org>,
       Thomas Gleixner <tglx@linutronix.de>
Subject: Re: A quick fio test (was Re: [patch 00/13] Syslets, "Threadlets", generic AIO support, v3)
Message-ID: <20070223162508.GA16782@kernel.dk>
References: <20070221211355.GA7302@elte.hu> <20070223125247.GO5737@kernel.dk> <20070223135525.GA31569@in.ibm.com> <20070223145826.GA32465@elte.hu> <20070223151515.GA12960@in.ibm.com>
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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.

-- 
Jens Axboe

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