From: Jens Axboe <axboe@kernel.dk>
To: Alket Memushaj <amemushaj@gmail.com>, fio@vger.kernel.org
Subject: Re: dedupe and replay
Date: Fri, 26 Sep 2014 13:08:39 -0600 [thread overview]
Message-ID: <5425B9B7.2080003@kernel.dk> (raw)
In-Reply-To: <CA+BkS8NvVNyj3KDy3UjtD2G0q-B3Ai7sdbqwRu_DafLQmKk37Q@mail.gmail.com>
On 09/26/2014 12:30 PM, Alket Memushaj wrote:
> Hi,
>
> I am playing with the dedupe option and while it works well under
> synthetic tests, it doesn't seem to work when replaying a trace.
>
> My test jobs are simple:
>
> fio --name=replay --ioengine=libaio --direct=1 --iodepth=32
> --read_iolog=/path/to/trace --dedupe_percentage=80
That should work, as far as I can tell, since we do the buffer fill
after the iolog retrieval has filled out an IO unit for us. Can you say
more about what doesn't appear to work?
> I understand that block sizes would be variable during a trace replay,
> but is it possible to specify a base block size and calculate dedupe
> based on that for blocks that are multiples of the base size?
Ah, that might be the key element here. Yes, the dedupe part might not
really work well for multiple write sizes. Nothing that inherently
prevents that from working, just didn't add that bit yet. Will do that.
--
Jens Axboe
next prev parent reply other threads:[~2014-09-26 19:08 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-26 18:30 dedupe and replay Alket Memushaj
2014-09-26 19:08 ` Jens Axboe [this message]
2014-09-26 19:38 ` Jens Axboe
2014-09-27 11:19 ` Alket Memushaj
2014-09-27 13:45 ` Jens Axboe
2014-09-27 14:02 ` Jens Axboe
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=5425B9B7.2080003@kernel.dk \
--to=axboe@kernel.dk \
--cc=amemushaj@gmail.com \
--cc=fio@vger.kernel.org \
/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.