From: Matthew Wilcox Subject: Re: Is TRIM/DISCARD going to be a performance problem? Date: Mon, 11 May 2009 06:48:22 -0600 Message-ID: <20090511124822.GD8112@parisc-linux.org> References: <20090510165259.GA31850@logfs.org> <20090511083754.GA29082@mit.edu> <20090511100624.GB6585@logfs.org> <20090511112729.GD29082@mit.edu> <20090511124325.GC6585@logfs.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Theodore Tso , Matthew Wilcox , Jens Axboe , Ric Wheeler , linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org To: J??rn Engel Return-path: Received: from palinux.external.hp.com ([192.25.206.14]:33481 "EHLO mail.parisc-linux.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752169AbZEKMsW (ORCPT ); Mon, 11 May 2009 08:48:22 -0400 Content-Disposition: inline In-Reply-To: <20090511124325.GC6585@logfs.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Mon, May 11, 2009 at 02:43:25PM +0200, J??rn Engel wrote: > Given the hardware braindamage it is relatively sane. As always, it > would be much better to fix the problem and not add workarounds, but we > seem to lack the gods favor this time around. > > Can't anyone explain to the SATA folks that a discard is much closer to > a write than to a secure erase or some other rare and slow command? I've heard the ATA committee are working on an NCQ version of TRIM. Don't expect support soon. -- Matthew Wilcox Intel Open Source Technology Centre "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step."