From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Lord Subject: Re: [RFC 1/2] block: implement an unprep function corresponding directly to prep Date: Mon, 02 Aug 2010 23:01:23 -0400 Message-ID: <4C578683.5010409@teksavvy.com> References: <1277917264.2839.153.camel@mulgrave.site> <20100701104653O.fujita.tomonori@lab.ntt.co.jp> <20100702110343.GA27159@lst.de> <20100705160023S.fujita.tomonori@lab.ntt.co.jp> <20100705192413.GA24189@lst.de> <4C3253C0.8040900@teksavvy.com> <4C3254A3.6080709@teksavvy.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from ironport2-out.teksavvy.com ([206.248.154.181]:43523 "EHLO ironport2-out.pppoe.ca" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752835Ab0HCDBZ (ORCPT ); Mon, 2 Aug 2010 23:01:25 -0400 In-Reply-To: <4C3254A3.6080709@teksavvy.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Christoph Hellwig Cc: FUJITA Tomonori , James.Bottomley@suse.de, snitzer@redhat.com, axboe@kernel.dk, linux-scsi@vger.kernel.org, dm-devel@redhat.com, linux-ide@vger.kernel.org On 10-07-05 05:54 PM, Mark Lord wrote: >> On 05/07/10 03:24 PM, Christoph Hellwig wrote: >>> >>> What codebase were you testing on? Sorry, but curently I'm a bit lost >>> in the maze of patches. I've got both and intel and an OCZ SSD > .. > > Do you, or anyone else with one, know what the upper limit is on > TRIM operations with the Intel SSDs ? > > I need to know the maximum amount of TRIM ranges they will process > in a single command. > > Eg. Indilinx-based SSDs don't appear to have a limit -- they'll accept > a TRIM command with thousands of LBA ranges included. > > Sandforce-based SSDs appear to restrict things to max 4KB of range data. > > So.. what about Intel? Well, I still don't know about Intel drives -- anyone? But for the latest hardware, some manufacturers are now reporting their TRIM limits in word[105] of the identify data, as described (optional) in the latest draft ATA ACS-2 specs. It appears that Sandforce drives officially only allow 512-bytes of range data. So I'll limit hdparm's TRIM functions to match word[105] when it is specified. The Indilinx drives I have here don't report anything in word[105], though. Cheers