From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: Re: ext4 vs btrfs performance on SSD array Date: Tue, 2 Sep 2014 07:31:04 -0400 Message-ID: <20140902113104.GD5049@thunk.org> References: <20140902000822.GA20473@dastard> <20140902012222.GA21405@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Dave Chinner , Nikolai Grigoriev , linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-raid@vger.kernel.org, linux-mm@kvack.org, Jens Axboe To: Christoph Hellwig Return-path: Content-Disposition: inline In-Reply-To: <20140902012222.GA21405@infradead.org> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org