From: "Theodore Ts'o" <tytso@mit.edu>
To: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>,
Nikolai Grigoriev <ngrigoriev@gmail.com>,
linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-raid@vger.kernel.org, linux-mm@kvack.org,
Jens Axboe <axboe@kernel.dk>
Subject: Re: ext4 vs btrfs performance on SSD array
Date: Tue, 2 Sep 2014 07:31:04 -0400 [thread overview]
Message-ID: <20140902113104.GD5049@thunk.org> (raw)
In-Reply-To: <20140902012222.GA21405@infradead.org>
> - the very small max readahead size
For things like the readahead size, that's probably something that we
should autotune, based the time it takes to read N sectors. i.e.,
start N relatively small, such as 128k, and then bump it up based on
how long it takes to do a sequential read of N sectors until it hits a
given tunable, which is specified in milliseconds instead of kilobytes.
> - replacing cfq with deadline (or noop)
Unfortunately, that will break ionice and a number of other things...
- Ted
WARNING: multiple messages have this Message-ID (diff)
From: Theodore Ts'o <tytso@mit.edu>
To: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>,
Nikolai Grigoriev <ngrigoriev@gmail.com>,
linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-raid@vger.kernel.org, linux-mm@kvack.org,
Jens Axboe <axboe@kernel.dk>
Subject: Re: ext4 vs btrfs performance on SSD array
Date: Tue, 2 Sep 2014 07:31:04 -0400 [thread overview]
Message-ID: <20140902113104.GD5049@thunk.org> (raw)
In-Reply-To: <20140902012222.GA21405@infradead.org>
> - the very small max readahead size
For things like the readahead size, that's probably something that we
should autotune, based the time it takes to read N sectors. i.e.,
start N relatively small, such as 128k, and then bump it up based on
how long it takes to do a sequential read of N sectors until it hits a
given tunable, which is specified in milliseconds instead of kilobytes.
> - replacing cfq with deadline (or noop)
Unfortunately, that will break ionice and a number of other things...
- Ted
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next prev parent reply other threads:[~2014-09-02 11:33 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-26 23:39 ext4 vs btrfs performance on SSD array Nikolai Grigoriev
2014-08-27 7:10 ` Duncan
2014-08-27 21:59 ` Nikolai Grigoriev
2014-09-02 0:08 ` Dave Chinner
2014-09-02 1:22 ` Christoph Hellwig
2014-09-02 1:22 ` Christoph Hellwig
2014-09-02 10:39 ` Zack Coffey
2014-09-02 11:31 ` Theodore Ts'o [this message]
2014-09-02 11:31 ` Theodore Ts'o
2014-09-02 14:20 ` Jan Kara
2014-09-02 14:20 ` Jan Kara
2014-09-02 14:55 ` Theodore Ts'o
2014-09-02 14:55 ` Theodore Ts'o
2014-09-02 12:55 ` Zack Coffey
2014-09-02 12:55 ` Zack Coffey
2014-09-02 13:40 ` Austin S Hemmelgarn
2014-09-03 0:01 ` NeilBrown
2014-09-05 16:08 ` Christoph Hellwig
2014-09-05 16:08 ` Christoph Hellwig
2014-09-05 16:40 ` Jeff Moyer
2014-09-05 16:40 ` Jeff Moyer
2014-09-05 16:50 ` Jens Axboe
2014-09-05 16:50 ` Jens Axboe
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