From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from magic.merlins.org ([209.81.13.136]:44961 "EHLO mail1.merlins.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753563AbaCNCMD (ORCPT ); Thu, 13 Mar 2014 22:12:03 -0400 Date: Thu, 13 Mar 2014 19:11:59 -0700 From: Marc MERLIN To: Hugo Mills , =?iso-8859-1?Q?Sw=E2mi?= Petaramesh , Martin Steigerwald , linux-btrfs@vger.kernel.org Subject: Re: discard synchronous on most SSDs? Message-ID: <20140314021159.GQ18959@merlins.org> References: <531C1CC4.701@gmail.com> <1553599.dDs6U900Vh@tethys> <3438733.p6vCjojJlH@merkaba> <1756989.4ep0Vdupld@tethys> <20140309113350.GH6318@carfax.org.uk> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="45Z9DzgjV8m4Oswq" In-Reply-To: <20140309113350.GH6318@carfax.org.uk> Sender: linux-btrfs-owner@vger.kernel.org List-ID: --45Z9DzgjV8m4Oswq Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Mar 09, 2014 at 11:33:50AM +0000, Hugo Mills wrote: > discard is, except on the very latest hardware, a synchronous command > (it's a limitation of the SATA standard), and therefore results in > very very poor performance. Interesting. How do I know if a given SSD will hang on discard? Is a Samsung EVO 840 1TB SSD latest hardware enough, or not? :) Thanks Marc --=20 "A mouse is a device used to point at the xterm you want to type in" - A.S.= R. Microsoft is to operating systems .... .... what McDonalds is to gourmet coo= king Home page: http://marc.merlins.org/ =20 --45Z9DzgjV8m4Oswq Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.15 (GNU/Linux) iQCVAwUBUyJlb34xUKZ2O+kBAQKPbgQAusAYg8v1FXtgWhWmeKMUnpdLpSNxf6pv bU5ucrZQLzx7MPoeKYgdTL4ilZLhiI96zXwTjfo6004FJrA3Qy0CZfmo6iygS7n3 tjg/nD4X2Yk1wmD/3GF65a6MNLotCS1NNPl9g9KCQY3sra0j5z32yfNLQZQ506QM m3p8TPll/As= =Gumt -----END PGP SIGNATURE----- --45Z9DzgjV8m4Oswq--