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Date: Thu, 07 Jul 2011 14:08:21 +0800
From: Shaohua Li <shaohua.li@...el.com>
To: Vivek Goyal <vgoyal@...hat.com>
Cc: lkml <linux-kernel@...r.kernel.org>,
Jens Axboe <jaxboe@...ionio.com>
Subject: Re: [PATCH 3/3]Subject: CFQ: add think time check for group
On Wed, 2011-07-06 at 23:06 +0800, Vivek Goyal wrote:
> On Wed, Jul 06, 2011 at 09:58:40AM +0800, Shaohua Li wrote:
> [..]
> > > > [global]
> > > > runtime=30
> > > > direct=1
> > > >
> > > > [test1]
> > > > cgroup=test1
> > > > cgroup_weight=1000
> > > > rw=randread
> > > > ioengine=libaio
> > > > size=500m
> > > > runtime=30
> > > > directory=/mnt
> > > > filename=file1
> > > > thinktime=9000
> > > >
> > > > [test2]
> > > > cgroup=test2
> > > > cgroup_weight=1000
> > > > rw=randread
> > > > ioengine=libaio
> > > > size=500m
> > > > runtime=30
> > > > directory=/mnt
> > > > filename=file2
> > > >
> > > > patched base
> > > > test1 64k 39k
> > > > test2 540k 540k
> > > > total 604k 578k
> > > >
> > > > group1 gets much better throughput because it waits less time.
>
> I don't understand it. Thinktime of group test1 is more than 8ms. So now
> we should not be idling on test1. Hence test1 should lose some share and
> test2 should gain disk share and overall throughput should go up.
>
> I am wondering why throughput of test2 did not go up?
hmm, actually the throughput of test2 is better. Maybe I wrote it down wrong.
test2 throughput is about 548k/s. Sorry.
> Also can you run some tests to make sure that disk shares of regular
> workloads (thinktime less than 8ms) are not impacted.
I tried think time 2ms or no think time. there is no difference. the
result is quite stable.
Thanks,
Shaohua
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