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Date:   Tue, 19 Nov 2019 16:54:52 +0800
From:   Ming Lei <ming.lei@redhat.com>
To:     Dave Chinner <david@fromorbit.com>
Cc:     Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
        linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org,
        Jeff Moyer <jmoyer@redhat.com>,
        Dave Chinner <dchinner@redhat.com>,
        Eric Sandeen <sandeen@redhat.com>,
        Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
        Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Tejun Heo <tj@kernel.org>
Subject: Re: single aio thread is migrated crazily by scheduler
Message-ID: <20191119085452.GA8252@ming.t460p>
References: <20191114113153.GB4213@ming.t460p>
 <20191114235415.GL4614@dread.disaster.area>
 <20191115010824.GC4847@ming.t460p>
 <20191115045634.GN4614@dread.disaster.area>
 <20191115070843.GA24246@ming.t460p>
 <20191115234005.GO4614@dread.disaster.area>
 <20191118162633.GC32306@linux.vnet.ibm.com>
 <20191118211804.GW4614@dread.disaster.area>
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On Tue, Nov 19, 2019 at 08:18:04AM +1100, Dave Chinner wrote:
> On Mon, Nov 18, 2019 at 09:56:33PM +0530, Srikar Dronamraju wrote:
> > * Dave Chinner <david@fromorbit.com> [2019-11-16 10:40:05]:
> >=20
> > > On Fri, Nov 15, 2019 at 03:08:43PM +0800, Ming Lei wrote:
> > > > On Fri, Nov 15, 2019 at 03:56:34PM +1100, Dave Chinner wrote:
> > > > > On Fri, Nov 15, 2019 at 09:08:24AM +0800, Ming Lei wrote:
> > > > I can reproduce the issue with 4k block size on another RH system, =
and
> > > > the login info of that system has been shared to you in RH BZ.
> > > >=20
> > > > 1)
> > >=20
> > > Almost all the fio task migrations are coming from migration/X
> > > kernel threads. i.e it's the scheduler active balancing that is
> > > causing the fio thread to bounce around.
> > >=20
> >=20
> > Can we try with the below patch.
>=20
> That makes things much, much worse.

Yeah, it is same with my test result, basically the fio io thread
migration counts is increased from 5k to 8k.

Thanks,
Ming