From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755060AbZBCMdR (ORCPT ); Tue, 3 Feb 2009 07:33:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752006AbZBCMdA (ORCPT ); Tue, 3 Feb 2009 07:33:00 -0500 Received: from 82-117-125-11.tcdsl.calypso.net ([82.117.125.11]:51144 "EHLO smtp.drzeus.cx" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751495AbZBCMdA (ORCPT ); Tue, 3 Feb 2009 07:33:00 -0500 Date: Tue, 3 Feb 2009 13:32:42 +0100 From: Pierre Ossman To: Jens Axboe Cc: Hugh Dickins , James Bottomley , Grant Grundler , Greg Freemyer , Tejun Heo , Michael Tokarev , Kay Sievers , Bartlomiej Zolnierkiewicz , linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, Alan Cox Subject: Re: [PATCH] block: export SSD/non-rotational queue flag through sysfs Message-ID: <20090203133242.29904063@mjolnir.drzeus.cx> In-Reply-To: <20090116064818.GS30821@kernel.dk> References: <4964866D.8010503@msgid.tls.msk.ru> <1231342473.3282.19.camel@localhost.localdomain> <496ECBA0.60209@gmail.com> <87f94c370901150707h10506e99reaa40c23e32ab18c@mail.gmail.com> <1232035561.5966.48.camel@localhost.localdomain> <1232046039.5966.54.camel@localhost.localdomain> <1232061429.5966.87.camel@localhost.localdomain> <20090116064818.GS30821@kernel.dk> X-Mailer: Claws Mail 3.7.0 (GTK+ 2.14.7; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: multipart/signed; protocol="application/pgp-signature"; micalg=PGP-SHA1; boundary="=_freyr.drzeus.cx-18211-1233664376-0001-2" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is a MIME-formatted message. If you see this text it means that your E-mail software does not support MIME-formatted messages. --=_freyr.drzeus.cx-18211-1233664376-0001-2 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Fri, 16 Jan 2009 07:48:18 +0100 Jens Axboe wrote: >=20 > For non-queuing devices, I think our current check is a bit too drastic. > We probably want to change that to >=20 > int dont_plug(q) > { > return blk_queue_nonrot(q) && blk_queue_tagged(q); > } >=20 Please do. The MMC block driver sets nonrot as of late, but it is extremely dependent on merging. The command overhead is just silly, so to get anywhere near the speed numbers indicated in marketing you need large requests. It seems that too many confuse "non-rotational" with "low latency", which isn't always the same. :) Rgds --=20 -- Pierre Ossman Linux kernel, MMC maintainer http://www.kernel.org rdesktop, core developer http://www.rdesktop.org WARNING: This correspondence is being monitored by the Swedish government. Make sure your server uses encryption for SMTP traffic and consider using PGP for end-to-end encryption. --=_freyr.drzeus.cx-18211-1233664376-0001-2 Content-Type: application/pgp-signature; name="signature.asc" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (GNU/Linux) iEYEARECAAYFAkmIOXIACgkQ7b8eESbyJLjdVQCgqNVyBfYB9z9dVstnhmi75i4t GHkAoIi1mICX4UQmdcFWxF5fkUm/Zc1T =cPzc -----END PGP SIGNATURE----- --=_freyr.drzeus.cx-18211-1233664376-0001-2--