From: Bart Van Assche <Bart.VanAssche@wdc.com>
To: "mb@lightnvm.io" <mb@lightnvm.io>,
"axboe@kernel.dk" <axboe@kernel.dk>,
"loberman@redhat.com" <loberman@redhat.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
Damien Le Moal <Damien.LeMoal@wdc.com>
Subject: Re: [PATCH 0/2] null_blk: zone support
Date: Tue, 10 Jul 2018 18:49:17 +0000 [thread overview]
Message-ID: <ba99bc66928277b73cdbeb8579d739db0cf58639.camel@wdc.com> (raw)
In-Reply-To: <9225abd8-35de-641d-2d2b-7ed566fb9956@kernel.dk>
On Tue, 2018-07-10 at 12:45 -0600, Jens Axboe wrote:
> The difference between the job file and the
> workload run can be huge. Consider something really basic:
>
> [randwrites]
> bs=4k
> rw=randwrite
>
> which would be 100% random 4k writes. If I run this on a zoned device,
> then that'd turn into 100% sequential writes.
That's not correct. The ZBD code in the github pull request serializes writes
per zone, not globally.
> > What I derived from the fio source code is as follows (please correct me
> > if I got anything wrong):
> > * The purpose of the zonesize, zonerange and zoneskip job options is to
> > limit the I/O range to a single zone with size "zonesize". The I/O
> > pattern for zoned block devices is different: I/O happens in multiple
> > zones simultaneously. The number of zones to which I/O happens is
> > called the number of open zones.
>
> The only difference is that fio currently only has one zone active. When
> it finishes one, it goes to the next. See my above suggestion on adding
> the notion of open zones, which would extend this to more than 1.
Thanks, I will look into this.
Bart.
next prev parent reply other threads:[~2018-07-10 18:49 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-06 17:38 [PATCH 0/2] null_blk: zone support Matias Bjørling
2018-07-06 17:38 ` [PATCH 1/2] null_blk: move shared definitions to header file Matias Bjørling
2018-07-06 17:38 ` [PATCH 2/2] null_blk: add zone support Matias Bjørling
2018-07-06 17:45 ` [PATCH 0/2] null_blk: " Laurence Oberman
2018-07-09 7:54 ` Matias Bjørling
2018-07-09 16:34 ` Jens Axboe
2018-07-10 0:05 ` Bart Van Assche
2018-07-10 14:46 ` Jens Axboe
2018-07-10 16:47 ` Bart Van Assche
2018-07-10 18:45 ` Jens Axboe
2018-07-10 18:49 ` Bart Van Assche [this message]
2018-07-10 18:51 ` Jens Axboe
2018-08-09 20:51 ` Zoned block device support for fio (was: [PATCH 0/2] null_blk: zone support) Bart Van Assche
2018-08-09 21:03 ` Zoned block device support for fio Jens Axboe
2018-08-15 18:07 ` Bart Van Assche
2018-07-07 2:54 ` [PATCH 0/2] null_blk: zone support Jens Axboe
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