From: Keith Busch <kbusch@kernel.org> To: Heiner Litz <hlitz@ucsc.edu> Cc: "Damien Le Moal" <Damien.LeMoal@wdc.com>, "Javier González" <javier@javigon.com>, "Matias Bjørling" <mb@lightnvm.io>, "Matias Bjorling" <Matias.Bjorling@wdc.com>, "Christoph Hellwig" <hch@lst.de>, "Keith Busch" <Keith.Busch@wdc.com>, "linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>, "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>, "Sagi Grimberg" <sagi@grimberg.me>, "Jens Axboe" <axboe@kernel.dk>, "Hans Holmberg" <Hans.Holmberg@wdc.com>, "Dmitry Fomichev" <Dmitry.Fomichev@wdc.com>, "Ajay Joshi" <Ajay.Joshi@wdc.com>, "Aravind Ramesh" <Aravind.Ramesh@wdc.com>, "Niklas Cassel" <Niklas.Cassel@wdc.com>, "Judy Brock" <judy.brock@samsung.com> Subject: Re: [PATCH 5/5] nvme: support for zoned namespaces Date: Thu, 18 Jun 2020 15:19:45 -0600 [thread overview] Message-ID: <20200618211945.GA2347@C02WT3WMHTD6> (raw) In-Reply-To: <CAJbgVnVnqGQiLx1PctDhAKkjLXRKFwr00tdTPJjkaXZDc+V6Bg@mail.gmail.com> On Thu, Jun 18, 2020 at 01:47:20PM -0700, Heiner Litz wrote: > the striping explanation makes sense. In this case will rephase to: It > is sufficient to support large enough un-splittable writes to achieve > full per-zone bandwidth with a single writer/single QD. This is subject to the capabilities of the device and software's memory constraints. The maximum DMA size for a single request an nvme device can handle often range anywhere from 64k to 4MB. The pci nvme driver maxes out at 4MB anyway because that's the most we can guarantee forward progress right now, otherwise the scatter lists become to big to ensure we'll be able to allocate one to dispatch a write command. We do report the size and the alignment constraints so that it won't get split, but we still have to work with applications that don't abide by those constraints. > My main point is: There is no fundamental reason for splitting up > requests intermittently just to re-assemble them in the same form > later.
WARNING: multiple messages have this Message-ID (diff)
From: Keith Busch <kbusch@kernel.org> To: Heiner Litz <hlitz@ucsc.edu> Cc: "Jens Axboe" <axboe@kernel.dk>, "Niklas Cassel" <Niklas.Cassel@wdc.com>, "Damien Le Moal" <Damien.LeMoal@wdc.com>, "Ajay Joshi" <Ajay.Joshi@wdc.com>, "Sagi Grimberg" <sagi@grimberg.me>, "Keith Busch" <Keith.Busch@wdc.com>, "Dmitry Fomichev" <Dmitry.Fomichev@wdc.com>, "Aravind Ramesh" <Aravind.Ramesh@wdc.com>, "Javier González" <javier@javigon.com>, "linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>, "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>, "Hans Holmberg" <Hans.Holmberg@wdc.com>, "Matias Bjørling" <mb@lightnvm.io>, "Judy Brock" <judy.brock@samsung.com>, "Christoph Hellwig" <hch@lst.de>, "Matias Bjorling" <Matias.Bjorling@wdc.com> Subject: Re: [PATCH 5/5] nvme: support for zoned namespaces Date: Thu, 18 Jun 2020 15:19:45 -0600 [thread overview] Message-ID: <20200618211945.GA2347@C02WT3WMHTD6> (raw) In-Reply-To: <CAJbgVnVnqGQiLx1PctDhAKkjLXRKFwr00tdTPJjkaXZDc+V6Bg@mail.gmail.com> On Thu, Jun 18, 2020 at 01:47:20PM -0700, Heiner Litz wrote: > the striping explanation makes sense. In this case will rephase to: It > is sufficient to support large enough un-splittable writes to achieve > full per-zone bandwidth with a single writer/single QD. This is subject to the capabilities of the device and software's memory constraints. The maximum DMA size for a single request an nvme device can handle often range anywhere from 64k to 4MB. The pci nvme driver maxes out at 4MB anyway because that's the most we can guarantee forward progress right now, otherwise the scatter lists become to big to ensure we'll be able to allocate one to dispatch a write command. We do report the size and the alignment constraints so that it won't get split, but we still have to work with applications that don't abide by those constraints. > My main point is: There is no fundamental reason for splitting up > requests intermittently just to re-assemble them in the same form > later. _______________________________________________ linux-nvme mailing list linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme
next prev parent reply other threads:[~2020-06-18 21:19 UTC|newest] Thread overview: 192+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-06-15 23:34 [PATCH 0/5] nvme support for zoned namespace command set Keith Busch 2020-06-15 23:34 ` Keith Busch 2020-06-15 23:34 ` [PATCH 1/5] block: add capacity field to zone descriptors Keith Busch 2020-06-15 23:34 ` Keith Busch 2020-06-15 23:49 ` Chaitanya Kulkarni 2020-06-15 23:49 ` Chaitanya Kulkarni 2020-06-16 10:28 ` Javier González 2020-06-16 10:28 ` Javier González 2020-06-16 13:47 ` Daniel Wagner 2020-06-16 13:47 ` Daniel Wagner 2020-06-16 13:54 ` Johannes Thumshirn 2020-06-16 13:54 ` Johannes Thumshirn 2020-06-16 15:41 ` Martin K. Petersen 2020-06-16 15:41 ` Martin K. Petersen 2020-06-15 23:34 ` [PATCH 2/5] null_blk: introduce zone capacity for zoned device Keith Busch 2020-06-15 23:34 ` Keith Busch 2020-06-15 23:46 ` Chaitanya Kulkarni 2020-06-15 23:46 ` Chaitanya Kulkarni 2020-06-16 14:18 ` Daniel Wagner 2020-06-16 14:18 ` Daniel Wagner 2020-06-16 15:48 ` Martin K. Petersen 2020-06-16 15:48 ` Martin K. Petersen 2020-06-15 23:34 ` [PATCH 3/5] nvme: implement I/O Command Sets Command Set support Keith Busch 2020-06-15 23:34 ` Keith Busch 2020-06-16 10:33 ` Javier González 2020-06-16 10:33 ` Javier González 2020-06-16 17:14 ` Niklas Cassel 2020-06-16 17:14 ` Niklas Cassel 2020-06-16 15:58 ` Martin K. Petersen 2020-06-16 15:58 ` Martin K. Petersen 2020-06-16 17:01 ` Keith Busch 2020-06-16 17:01 ` Keith Busch 2020-06-17 9:50 ` Niklas Cassel 2020-06-17 9:50 ` Niklas Cassel 2020-06-16 17:06 ` Niklas Cassel 2020-06-16 17:06 ` Niklas Cassel 2020-06-17 2:01 ` Martin K. Petersen 2020-06-17 2:01 ` Martin K. Petersen 2020-06-15 23:34 ` [PATCH 4/5] nvme: support for multi-command set effects Keith Busch 2020-06-15 23:34 ` Keith Busch 2020-06-16 10:34 ` Javier González 2020-06-16 10:34 ` Javier González 2020-06-16 16:03 ` Martin K. Petersen 2020-06-16 16:03 ` Martin K. Petersen 2020-06-15 23:34 ` [PATCH 5/5] nvme: support for zoned namespaces Keith Busch 2020-06-15 23:34 ` Keith Busch 2020-06-16 10:41 ` Javier González 2020-06-16 10:41 ` Javier González 2020-06-16 11:18 ` Matias Bjørling 2020-06-16 11:18 ` Matias Bjørling 2020-06-16 12:00 ` Javier González 2020-06-16 12:00 ` Javier González 2020-06-16 12:06 ` Matias Bjørling 2020-06-16 12:06 ` Matias Bjørling 2020-06-16 12:24 ` Javier González 2020-06-16 12:24 ` Javier González 2020-06-16 12:27 ` Matias Bjørling 2020-06-16 12:27 ` Matias Bjørling 2020-06-16 12:35 ` Damien Le Moal 2020-06-16 12:35 ` Damien Le Moal [not found] ` <CGME20200616130815uscas1p1be34e5fceaa548eac31fb30790a689d4@uscas1p1.samsung.com> 2020-06-16 13:08 ` Judy Brock 2020-06-16 13:08 ` Judy Brock 2020-06-16 13:32 ` Matias Bjørling 2020-06-16 13:32 ` Matias Bjørling 2020-06-16 13:34 ` Damien Le Moal 2020-06-16 13:34 ` Damien Le Moal 2020-06-16 14:16 ` Javier González 2020-06-16 14:16 ` Javier González 2020-06-16 14:42 ` Damien Le Moal 2020-06-16 14:42 ` Damien Le Moal 2020-06-16 15:02 ` Javier González 2020-06-16 15:02 ` Javier González 2020-06-16 15:20 ` Matias Bjørling 2020-06-16 15:20 ` Matias Bjørling 2020-06-16 16:03 ` Javier González 2020-06-16 16:03 ` Javier González 2020-06-16 16:07 ` Matias Bjorling 2020-06-16 16:07 ` Matias Bjorling 2020-06-16 16:21 ` Javier González 2020-06-16 16:21 ` Javier González 2020-06-16 16:25 ` Matias Bjørling 2020-06-16 16:25 ` Matias Bjørling 2020-06-16 15:48 ` Keith Busch 2020-06-16 15:48 ` Keith Busch 2020-06-16 15:55 ` Javier González 2020-06-16 15:55 ` Javier González 2020-06-16 16:04 ` Matias Bjorling 2020-06-16 16:04 ` Matias Bjorling 2020-06-16 16:07 ` Keith Busch 2020-06-16 16:07 ` Keith Busch 2020-06-16 16:13 ` Javier González 2020-06-16 16:13 ` Javier González 2020-06-17 0:38 ` Damien Le Moal 2020-06-17 0:38 ` Damien Le Moal 2020-06-17 6:18 ` Javier González 2020-06-17 6:18 ` Javier González 2020-06-17 6:54 ` Damien Le Moal 2020-06-17 6:54 ` Damien Le Moal 2020-06-17 7:11 ` Javier González 2020-06-17 7:11 ` Javier González 2020-06-17 7:29 ` Damien Le Moal 2020-06-17 7:29 ` Damien Le Moal 2020-06-17 7:34 ` Javier González 2020-06-17 7:34 ` Javier González 2020-06-17 0:14 ` Damien Le Moal 2020-06-17 0:14 ` Damien Le Moal 2020-06-17 6:09 ` Javier González 2020-06-17 6:09 ` Javier González 2020-06-17 6:47 ` Damien Le Moal 2020-06-17 6:47 ` Damien Le Moal 2020-06-17 7:02 ` Javier González 2020-06-17 7:02 ` Javier González 2020-06-17 7:24 ` Damien Le Moal 2020-06-17 7:24 ` Damien Le Moal 2020-06-17 7:29 ` Javier González 2020-06-17 7:29 ` Javier González [not found] ` <CGME20200616123503uscas1p22ce22054a1b4152a20437b5abdd55119@uscas1p2.samsung.com> 2020-06-16 12:35 ` Judy Brock 2020-06-16 12:35 ` Judy Brock 2020-06-16 12:37 ` Damien Le Moal 2020-06-16 12:37 ` Damien Le Moal 2020-06-16 12:37 ` Matias Bjørling 2020-06-16 12:37 ` Matias Bjørling 2020-06-16 13:12 ` Judy Brock 2020-06-16 13:12 ` Judy Brock 2020-06-16 13:18 ` Judy Brock 2020-06-16 13:18 ` Judy Brock 2020-06-16 13:32 ` Judy Brock 2020-06-16 13:32 ` Judy Brock 2020-06-16 13:39 ` Damien Le Moal 2020-06-16 13:39 ` Damien Le Moal 2020-06-17 7:43 ` Christoph Hellwig 2020-06-17 7:43 ` Christoph Hellwig 2020-06-17 12:01 ` Martin K. Petersen 2020-06-17 12:01 ` Martin K. Petersen 2020-06-17 15:00 ` Javier González 2020-06-17 15:00 ` Javier González 2020-06-17 14:42 ` Javier González 2020-06-17 14:42 ` Javier González 2020-06-17 17:57 ` Matias Bjørling 2020-06-17 17:57 ` Matias Bjørling 2020-06-17 18:28 ` Javier González 2020-06-17 18:28 ` Javier González 2020-06-17 18:55 ` Matias Bjorling 2020-06-17 18:55 ` Matias Bjorling 2020-06-17 19:09 ` Javier González 2020-06-17 19:09 ` Javier González 2020-06-17 19:23 ` Matias Bjørling 2020-06-17 19:23 ` Matias Bjørling 2020-06-17 19:40 ` Javier González 2020-06-17 19:40 ` Javier González 2020-06-17 23:44 ` Heiner Litz 2020-06-17 23:44 ` Heiner Litz 2020-06-18 1:55 ` Keith Busch 2020-06-18 1:55 ` Keith Busch 2020-06-18 4:24 ` Heiner Litz 2020-06-18 4:24 ` Heiner Litz 2020-06-18 5:15 ` Damien Le Moal 2020-06-18 5:15 ` Damien Le Moal 2020-06-18 20:47 ` Heiner Litz 2020-06-18 20:47 ` Heiner Litz 2020-06-18 21:04 ` Matias Bjorling 2020-06-18 21:04 ` Matias Bjorling 2020-06-18 21:19 ` Keith Busch [this message] 2020-06-18 21:19 ` Keith Busch 2020-06-18 22:05 ` Heiner Litz 2020-06-18 22:05 ` Heiner Litz 2020-06-19 0:57 ` Damien Le Moal 2020-06-19 0:57 ` Damien Le Moal 2020-06-19 10:29 ` Matias Bjorling 2020-06-19 10:29 ` Matias Bjorling 2020-06-19 18:08 ` Heiner Litz 2020-06-19 18:08 ` Heiner Litz 2020-06-19 18:10 ` Keith Busch 2020-06-19 18:10 ` Keith Busch 2020-06-19 18:17 ` Heiner Litz 2020-06-19 18:17 ` Heiner Litz 2020-06-19 18:22 ` Keith Busch 2020-06-19 18:22 ` Keith Busch 2020-06-19 18:25 ` Matias Bjørling 2020-06-19 18:25 ` Matias Bjørling 2020-06-19 18:40 ` Heiner Litz 2020-06-19 18:40 ` Heiner Litz 2020-06-19 18:18 ` Matias Bjørling 2020-06-19 18:18 ` Matias Bjørling 2020-06-20 6:33 ` Christoph Hellwig 2020-06-20 6:33 ` Christoph Hellwig 2020-06-20 17:52 ` Heiner Litz 2020-06-20 17:52 ` Heiner Litz 2020-06-22 14:01 ` Christoph Hellwig 2022-03-02 21:11 ` Luis Chamberlain 2020-06-17 2:08 ` Martin K. Petersen 2020-06-17 2:08 ` Martin K. Petersen
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