From: Damien Le Moal <Damien.LeMoal@wdc.com>
To: Bart Van Assche <bvanassche@acm.org>,
Changheun Lee <nanich.lee@samsung.com>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
Cc: Johannes Thumshirn <Johannes.Thumshirn@wdc.com>,
"asml.silence@gmail.com" <asml.silence@gmail.com>,
"axboe@kernel.dk" <axboe@kernel.dk>,
"hch@infradead.org" <hch@infradead.org>,
"jisoo2146.oh@samsung.com" <jisoo2146.oh@samsung.com>,
"junho89.kim@samsung.com" <junho89.kim@samsung.com>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"ming.lei@redhat.com" <ming.lei@redhat.com>,
"mj0123.lee@samsung.com" <mj0123.lee@samsung.com>,
"osandov@fb.com" <osandov@fb.com>,
"patchwork-bot@kernel.org" <patchwork-bot@kernel.org>,
"seunghwan.hyun@samsung.com" <seunghwan.hyun@samsung.com>,
"sookwan7.kim@samsung.com" <sookwan7.kim@samsung.com>,
"tj@kernel.org" <tj@kernel.org>,
"tom.leiming@gmail.com" <tom.leiming@gmail.com>,
"woosung2.lee@samsung.com" <woosung2.lee@samsung.com>,
"yt0928.kim@samsung.com" <yt0928.kim@samsung.com>
Subject: Re: [RESEND,v5,1/2] bio: limit bio max size
Date: Sun, 11 Apr 2021 22:13:01 +0000 [thread overview]
Message-ID: <BL0PR04MB65148B0629FF23847341BAE8E7719@BL0PR04MB6514.namprd04.prod.outlook.com> (raw)
In-Reply-To: cdd26ed3-2013-7edd-b25e-557a56397614@acm.org
On 2021/04/09 23:47, Bart Van Assche wrote:
> On 4/7/21 3:27 AM, Damien Le Moal wrote:
>> On 2021/04/07 18:46, Changheun Lee wrote:
>>> I'll prepare new patch as you recommand. It will be added setting of
>>> limit_bio_size automatically when queue max sectors is determined.
>>
>> Please do that in the driver for the HW that benefits from it. Do not do this
>> for all block devices.
>
> Hmm ... is it ever useful to build a bio with a size that exceeds
> max_hw_sectors when submitting a bio directly to a block device, or in
> other words, if no stacked block driver sits between the submitter and
> the block device? Am I perhaps missing something?
Device performance wise, the benefits are certainly not obvious to me either.
But for very fast block devices, I think the CPU overhead of building more
smaller BIOs may be significant compared to splitting a large BIO into multiple
requests. Though it may be good to revisit this with some benchmark numbers.
>
> Thanks,
>
> Bart.
>
--
Damien Le Moal
Western Digital Research
next prev parent reply other threads:[~2021-04-11 22:13 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20210316080104epcas1p11483035c927c2e65600ae90309334b24@epcas1p1.samsung.com>
2021-03-16 7:44 ` [RESEND PATCH v5 1/2] bio: limit bio max size Changheun Lee
[not found] ` <CGME20210316080106epcas1p3522dda95e9c97fc39b40b008bbf87c04@epcas1p3.samsung.com>
2021-03-16 7:44 ` [RESEND PATCH v5 2/2] bio: add limit_bio_size sysfs Changheun Lee
2021-04-06 21:05 ` Bart Van Assche
[not found] ` <CGME20210407013850epcas1p2d305f138c9fa1431abba1ec44a382de9@epcas1p2.samsung.com>
2021-04-07 1:21 ` Changheun Lee
2021-04-07 5:43 ` Greg KH
[not found] ` <CGME20210406014905epcas1p16830a46b7ac6af95a0e2c2c6f4c04859@epcas1p1.samsung.com>
2021-04-06 1:31 ` [RESEND PATCH v5 1/2] bio: limit bio max size Changheun Lee
2021-04-06 7:32 ` Greg KH
[not found] ` <CGME20210407003345epcas1p21376df37d3dfe933684139d3beaf9c51@epcas1p2.samsung.com>
2021-04-07 0:16 ` Changheun Lee
2021-04-07 5:05 ` Greg KH
[not found] ` <CGME20210407052407epcas1p1d0b5d23ac04a68760f691954e7ada3dd@epcas1p1.samsung.com>
2021-04-07 5:06 ` Changheun Lee
2021-04-07 5:36 ` Greg KH
[not found] ` <CGME20210407071241epcas1p2559ea674299b686c9001326894c933bc@epcas1p2.samsung.com>
2021-04-07 6:55 ` Changheun Lee
2021-04-07 7:40 ` Greg KH
[not found] ` <CGME20210407094610epcas1p472207e8d3ca0e5e697974c993a2a34f7@epcas1p4.samsung.com>
2021-04-07 9:28 ` [RESEND,v5,1/2] " Changheun Lee
2021-04-07 10:27 ` Damien Le Moal
2021-04-09 14:47 ` Bart Van Assche
2021-04-11 22:13 ` Damien Le Moal [this message]
2021-04-12 3:23 ` Ming Lei
[not found] ` <CGME20210413045517epcas1p32b058646dd795e59389401ca997c4cac@epcas1p3.samsung.com>
2021-04-13 4:37 ` Changheun Lee
2021-04-13 5:32 ` Christoph Hellwig
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=BL0PR04MB65148B0629FF23847341BAE8E7719@BL0PR04MB6514.namprd04.prod.outlook.com \
--to=damien.lemoal@wdc.com \
--cc=Johannes.Thumshirn@wdc.com \
--cc=asml.silence@gmail.com \
--cc=axboe@kernel.dk \
--cc=bvanassche@acm.org \
--cc=gregkh@linuxfoundation.org \
--cc=hch@infradead.org \
--cc=jisoo2146.oh@samsung.com \
--cc=junho89.kim@samsung.com \
--cc=linux-block@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=ming.lei@redhat.com \
--cc=mj0123.lee@samsung.com \
--cc=nanich.lee@samsung.com \
--cc=osandov@fb.com \
--cc=patchwork-bot@kernel.org \
--cc=seunghwan.hyun@samsung.com \
--cc=sookwan7.kim@samsung.com \
--cc=tj@kernel.org \
--cc=tom.leiming@gmail.com \
--cc=woosung2.lee@samsung.com \
--cc=yt0928.kim@samsung.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).