Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
IronPort-SDR: DGmXEaYf4p71WlXzu8rl3JiLxVtqmrWsyTa35Vut3X37Ohodte4KpOydOIEkpq4cf6UjGE6xxm
 OW+JiT6KgVlsi/nJRlyQmp9OXxV8JP0jVbwywT1pSJ4KK5gRxhmCDDzFO6We7/0yjXk8ANhFpw
 z6Z4pVQfWH4KrDnhENrBfpPIBmfwW1ZJW4mjnhRpbfJgJg7z1kNU0G5WVO8+1KzE7ECUEjb7Pt
 hd2df+DyoV5/b2KKEW0GvP37O5gskaSvuoS6nkRyE4rVSZ1QteR5XFvTRsRhWCk7tNX34+B0S6
 glY=
From:   Damien Le Moal <Damien.LeMoal@wdc.com>
To:     Randy Dunlap <rdunlap@infradead.org>,
        "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
        "linux-xfs@vger.kernel.org" <linux-xfs@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>
CC:     Johannes Thumshirn <jth@kernel.org>,
        Naohiro Aota <Naohiro.Aota@wdc.com>,
        "Darrick J . Wong" <darrick.wong@oracle.com>,
        Hannes Reinecke <hare@suse.de>
Subject: Re: [PATCH v6 2/2] zonefs: Add documentation
Thread-Topic: [PATCH v6 2/2] zonefs: Add documentation
Thread-Index: AQHVxf7Snqi2k881OEaR6BUy1rYblA==
Date:   Wed, 15 Jan 2020 06:23:21 +0000
Message-ID: <BYAPR04MB5816BB7B5946E4E8643F9DC3E7370@BYAPR04MB5816.namprd04.prod.outlook.com>
References: <20200108083649.450834-1-damien.lemoal@wdc.com>
 <20200108083649.450834-3-damien.lemoal@wdc.com>
 <c9f37661-03a0-22e3-4b99-b97c47917b5d@infradead.org>
Accept-Language: en-US
Content-Language: en-US
wdcipoutbound: EOP-TRUE
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-Network-Message-Id: b5750383-3455-400d-8d64-08d799836b22
X-MS-Exchange-CrossTenant-originalarrivaltime: 15 Jan 2020 06:23:21.1997
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: b61c8803-16f3-4c35-9b17-6f65f441df86
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-CrossTenant-userprincipalname: O9HhkHjoBRXwaPm+ObpjtZxSBuuzCpRiNjotPvx5d/8h6Oe7UnVNO0Qu6058vlA7wteEOvipo8OCmNkfGp3Z4A==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR04MB4261
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Randy,=0A=
=0A=
On 2020/01/15 3:25, Randy Dunlap wrote:=0A=
> Hi Damien,=0A=
> =0A=
> Here are a few editorial comments for you...=0A=
=0A=
Thanks ! All fixed.=0A=
=0A=
[...]=0A=
>> +For sequential write zone files, the file size changes as data is appen=
ded at=0A=
>> +the end of the file, similarly to any regular file system.=0A=
>> +=0A=
>> +# dd if=3D/dev/zero of=3D/mnt/seq/0 bs=3D4096 count=3D1 conv=3Dnotrunc =
oflag=3Ddirect=0A=
>> +1+0 records in=0A=
>> +1+0 records out=0A=
>> +4096 bytes (4.1 kB, 4.0 KiB) copied, 1.05112 s, 3.9 kB/s=0A=
> =0A=
> Still slow.  You don't want to change that?=0A=
=0A=
Good catch. I thought I had fixed that. Here is the updated dd run,=0A=
after making sure that the disk has woken up from low power state before=0A=
running:=0A=
=0A=
dd if=3D/dev/zero of=3D/mnt/seq/0 bs=3D4096 count=3D1 conv=3Dnotrunc oflag=
=3Ddirect=0A=
1+0 records in=0A=
1+0 records out=0A=
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.00044121 s, 9.3 MB/s=0A=
=0A=
The HDD write cache is on and empty at the time of running this, which=0A=
explains the much lower I/O time.=0A=
=0A=
-- =0A=
Damien Le Moal=0A=
Western Digital Research=0A=