From: Christoph Hellwig <hch@infradead.org>
To: Changheun Lee <nanich.lee@samsung.com>
Cc: hch@infradead.org, Johannes.Thumshirn@wdc.com,
alex_y_xu@yahoo.ca, asml.silence@gmail.com, axboe@kernel.dk,
bgoncalv@redhat.com, bvanassche@acm.org, damien.lemoal@wdc.com,
gregkh@linuxfoundation.org, jaegeuk@kernel.org,
jisoo2146.oh@samsung.com, junho89.kim@samsung.com,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
ming.lei@redhat.com, mj0123.lee@samsung.com, osandov@fb.com,
patchwork-bot@kernel.org, seunghwan.hyun@samsung.com,
sookwan7.kim@samsung.com, tj@kernel.org, tom.leiming@gmail.com,
woosung2.lee@samsung.com, yi.zhang@redhat.com,
yt0928.kim@samsung.com
Subject: Re: [PATCH v10 0/1] bio: limit bio max size
Date: Mon, 17 May 2021 11:11:36 +0100 [thread overview]
Message-ID: <YKJBWClI7sUeABDs@infradead.org> (raw)
In-Reply-To: <20210514063241.22260-1-nanich.lee@samsung.com>
On Fri, May 14, 2021 at 03:32:41PM +0900, Changheun Lee wrote:
> I tested 512MB file read with direct I/O. and chunk size is 64MB.
> - on SCSI disk, with no limit of bio max size(4GB) : avg. 630 MB/s
> - on SCSI disk, with limit bio max size to 1MB : avg. 645 MB/s
> - on ramdisk, with no limit of bio max size(4GB) : avg. 2749 MB/s
> - on ramdisk, with limit bio max size to 1MB : avg. 3068 MB/s
>
> I set ramdisk environment as below.
> - dd if=/dev/zero of=/mnt/ramdisk.img bs=$((1024*1024)) count=1024
> - mkfs.ext4 /mnt/ramdisk.img
> - mkdir /mnt/ext4ramdisk
> - mount -o loop /mnt/ramdisk.img /mnt/ext4ramdisk
>
> With low performance disk, bio submit delay caused by large bio size is
> not big protion. So it can't be feel easily. But it will be shown in high
> performance disk.
So let's attack the problem properly:
1) switch f2fs to a direct I/O implementation that does not suck
2) look into optimizing the iomap code to e.g. submit the bio once
it is larger than queue_io_opt() without failing to add to a bio
which would be annoying for things like huge pages.
next prev parent reply other threads:[~2021-05-17 10:12 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20210513102018epcas1p2a69f8e50cdf8380e433aea1a9303d04c@epcas1p2.samsung.com>
2021-05-13 10:02 ` [PATCH v10 0/1] bio: limit bio max size Changheun Lee
[not found] ` <CGME20210513102019epcas1p35d6740527dacd9bff7d8b07316e4cbfd@epcas1p3.samsung.com>
2021-05-13 10:02 ` [PATCH v10 1/1] " Changheun Lee
2021-05-13 11:23 ` [PATCH v10 0/1] " Christoph Hellwig
[not found] ` <CGME20210514065054epcas1p4bd5c92a59d4010da4447ef62f65fdd4b@epcas1p4.samsung.com>
2021-05-14 6:32 ` Changheun Lee
2021-05-17 10:11 ` Christoph Hellwig [this message]
[not found] ` <CGME20210526034859epcas1p3b3ab803406c983df431f89b6f9097f08@epcas1p3.samsung.com>
2021-05-26 3:30 ` Changheun Lee
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