From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id p079FNpF021857 for ; Fri, 7 Jan 2011 03:15:23 -0600 Received: from enyo.dsw2k3.info (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 3415C1D15E26 for ; Fri, 7 Jan 2011 01:17:32 -0800 (PST) Received: from enyo.dsw2k3.info (enyo.dsw2k3.info [195.71.86.239]) by cuda.sgi.com with ESMTP id 5vzJjJVycc07rQyI for ; Fri, 07 Jan 2011 01:17:32 -0800 (PST) Date: Fri, 7 Jan 2011 10:17:20 +0100 From: Matthias Schniedermeyer Subject: Re: TRIM details Message-ID: <20110107091720.GA6921@citd.de> References: <4D2686ED.7000304@philkarn.net> <20110107091120.GA6634@citd.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20110107091120.GA6634@citd.de> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: karn@ka9q.net Cc: xfs@oss.sgi.com On 07.01.2011 10:11, Matthias Schniedermeyer wrote: > On 06.01.2011 19:22, Phil Karn wrote: > > > Just have the drive interpret an ordinary write of all 0's to any LBA as > > an implicit "unmap" indication for that LBA. As long as the drive > > The drive would have to look into each written sector in the off chance > that it might be 0, that's a lot of electrons you have to burn for not > much gain. And that's ignoring the performance side, doing such a check > on each incoming write would be expensive at best. Altough, after thinking about it a little more. Doing a Population count in the controller while the data comes in over the wire can't be that expensive. Bis denn -- Real Programmers consider "what you see is what you get" to be just as bad a concept in Text Editors as it is in women. No, the Real Programmer wants a "you asked for it, you got it" text editor -- complicated, cryptic, powerful, unforgiving, dangerous. _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs