From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre Ossman Subject: Re: [PATCH 0/2] MMC discard support (was [PATCH 0/7] Discard requests, v2) Date: Sat, 16 Aug 2008 19:51:16 +0200 Message-ID: <20080816195116.6b872ccb@mjolnir.drzeus.cx> References: <20080816190858.4d150ea1@mjolnir.drzeus.cx> <1218908321.3184.249.camel@pmac.infradead.org> Mime-Version: 1.0 Content-Type: multipart/signed; protocol="application/pgp-signature"; micalg=PGP-SHA1; boundary="=_freyr.drzeus.cx-20704-1218909084-0001-2" Cc: linux-fsdevel@vger.kernel.org, Jens Axboe To: David Woodhouse Return-path: Received: from server.drzeus.cx ([85.8.24.28]:59430 "EHLO smtp.drzeus.cx" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751593AbYHPRvY (ORCPT ); Sat, 16 Aug 2008 13:51:24 -0400 In-Reply-To: <1218908321.3184.249.camel@pmac.infradead.org> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: 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-20704-1218909084-0001-2 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Sat, 16 Aug 2008 18:38:41 +0100 David Woodhouse wrote: > On Sat, 2008-08-16 at 19:08 +0200, Pierre Ossman wrote: > > I've cooked up some patches that maps David's new discard requests to > > erase operations on MMC and SD cards. I'm not entirely sure these are > > something to keep though as I've been unable to see any performance > > increase in keeping blocks erased. Do we have any other reason to keep > > it? >=20 > When you fill a file system completely, then delete all files -- then do > you see a performance improvement when you subsequently write to it? >=20 When testing the new version, I've first erased the entire device using the new ioctl. So the tests start with a completely erased device. Basically the following: ./discard /dev/mmcblk0 0 `cat /sys/block/mmcblk0/size` mkfs -t vfat /dev/mmcblk0 mount /dev/mmcblk0 /media/tmp bonnie++ -d /media/tmp The comparison is against a driver without erase support and a card prepared by filling it with /dev/zero. It might be that my testing methodology is flawed, so suggestions are welcome (and people testing on their own for that matter). --=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-20704-1218909084-0001-2 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) iEYEARECAAYFAkinE5oACgkQ7b8eESbyJLh54gCg12Kv1ECGDI7HMPlBfHjQcB2k dHEAoOdUwFYTx+K+HZyjb59FQPsAtj7c =fJf4 -----END PGP SIGNATURE----- --=_freyr.drzeus.cx-20704-1218909084-0001-2--