From: "Theodore Y. Ts'o" <tytso@mit.edu>
To: brookxu <brookxu.cn@gmail.com>
Cc: adilger.kernel@dilger.ca, riteshh@linux.ibm.com, jack@suse.cz,
linux-ext4@vger.kernel.org
Subject: Re: [PATCH v5 2/2] ext4: limit the length of per-inode prealloc list
Date: Wed, 19 Aug 2020 00:24:38 -0400 [thread overview]
Message-ID: <20200819042438.GF162457@mit.edu> (raw)
In-Reply-To: <d7a98178-056b-6db5-6bce-4ead23f4a257@gmail.com>
On Mon, Aug 17, 2020 at 03:36:15PM +0800, brookxu wrote:
> In the scenario of writing sparse files, the per-inode prealloc list may
> be very long, resulting in high overhead for ext4_mb_use_preallocated().
> To circumvent this problem, we limit the maximum length of per-inode
> prealloc list to 512 and allow users to modify it.
>
> After patching, we observed that the sys ratio of cpu has dropped, and
> the system throughput has increased significantly. We created a process
> to write the sparse file, and the running time of the process on the
> fixed kernel was significantly reduced, as follows:
>
> Running time on unfixed kernel:
> [root@TENCENT64 ~]# time taskset 0x01 ./sparse /data1/sparce.dat
> real 0m2.051s
> user 0m0.008s
> sys 0m2.026s
>
> Running time on fixed kernel:
> [root@TENCENT64 ~]# time taskset 0x01 ./sparse /data1/sparce.dat
> real 0m0.471s
> user 0m0.004s
> sys 0m0.395s
Thanks, applied with Ritesh's suggested spelling fix up.
- Ted
prev parent reply other threads:[~2020-08-19 4:24 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-17 7:36 [PATCH v5 2/2] ext4: limit the length of per-inode prealloc list brookxu
2020-08-18 3:09 ` Ritesh Harjani
2020-08-18 3:21 ` Ritesh Harjani
2020-08-18 9:58 ` brookxu
2020-08-19 4:24 ` Theodore Y. Ts'o [this message]
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=20200819042438.GF162457@mit.edu \
--to=tytso@mit.edu \
--cc=adilger.kernel@dilger.ca \
--cc=brookxu.cn@gmail.com \
--cc=jack@suse.cz \
--cc=linux-ext4@vger.kernel.org \
--cc=riteshh@linux.ibm.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.