From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-f173.google.com (mail-ob0-f173.google.com [209.85.214.173]) by kanga.kvack.org (Postfix) with ESMTP id 5A35C6B0036 for ; Fri, 5 Sep 2014 12:08:15 -0400 (EDT) Received: by mail-ob0-f173.google.com with SMTP id uy5so8899664obc.18 for ; Fri, 05 Sep 2014 09:08:15 -0700 (PDT) Received: from bombadil.infradead.org (bombadil.infradead.org. [2001:1868:205::9]) by mx.google.com with ESMTPS id v2si5009874pbz.101.2014.09.05.09.08.14 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 05 Sep 2014 09:08:14 -0700 (PDT) Date: Fri, 5 Sep 2014 09:08:08 -0700 From: Christoph Hellwig Subject: Re: ext4 vs btrfs performance on SSD array Message-ID: <20140905160808.GA7967@infradead.org> References: <20140902000822.GA20473@dastard> <20140902012222.GA21405@infradead.org> <20140903100158.34916d34@notabene.brown> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140903100158.34916d34@notabene.brown> Sender: owner-linux-mm@kvack.org List-ID: To: NeilBrown Cc: Christoph Hellwig , 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 On Wed, Sep 03, 2014 at 10:01:58AM +1000, NeilBrown wrote: > Do we still need maximums at all? I don't think we do. At least on any system I work with I have to increase them to get good performance without any adverse effect on throttling. > So can we just remove the limit on max_sectors and the RAID5 stripe cache > size? I'm certainly keen to remove the later and just use a mempool if the > limit isn't needed. > I have seen reports that a very large raid5 stripe cache size can cause > a reduction in performance. I don't know why but I suspect it is a bug that > should be found and fixed. > > Do we need max_sectors ?? I'll send a patch to remove it and watch for the fireworks.. -- 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