From owner-freebsd-stable@FreeBSD.ORG Sun Mar 8 18:39:04 2009 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 893FD1065675 for ; Sun, 8 Mar 2009 18:39:04 +0000 (UTC) (envelope-from freebsd-stable@m.gmane.org) Received: from ciao.gmane.org (main.gmane.org [80.91.229.2]) by mx1.freebsd.org (Postfix) with ESMTP id 1151E8FC20 for ; Sun, 8 Mar 2009 18:39:03 +0000 (UTC) (envelope-from freebsd-stable@m.gmane.org) Received: from list by ciao.gmane.org with local (Exim 4.43) id 1LgNtt-0002p9-J1 for freebsd-stable@freebsd.org; Sun, 08 Mar 2009 18:39:01 +0000 Received: from 93-138-99-130.adsl.net.t-com.hr ([93.138.99.130]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sun, 08 Mar 2009 18:39:01 +0000 Received: from ivoras by 93-138-99-130.adsl.net.t-com.hr with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sun, 08 Mar 2009 18:39:01 +0000 X-Injected-Via-Gmane: http://gmane.org/ To: freebsd-stable@freebsd.org From: Ivan Voras Date: Sun, 08 Mar 2009 19:38:30 +0100 Lines: 65 Message-ID: References: <20090308005515.GA68934@onelab2.iet.unipi.it> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig8F0B0F8DA61062B1221FE939" X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: 93-138-99-130.adsl.net.t-com.hr User-Agent: Thunderbird 2.0.0.19 (Windows/20081209) In-Reply-To: <20090308005515.GA68934@onelab2.iet.unipi.it> X-Enigmail-Version: 0.95.7 Sender: news Cc: freebsd-geom@freebsd.org Subject: Re: updated geom_sched code X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 08 Mar 2009 18:39:04 -0000 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig8F0B0F8DA61062B1221FE939 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Luigi Rizzo wrote: > Hi all, > this is an update on the work that Fabio Checconi and I are doing > on disk scheduling, which was first announced here a couple of > months ago: >=20 > http://lists.freebsd.org/pipermail/freebsd-stable/2009-January/0475= 97.html >=20 > Since the previous version, we have done some massive cleanup and > consolidation of the code, fixed a bug in the system's disksort, > and added amd64 support. > NOTE: due to the way we store classification info, the schedulers > are probably incompatible with g_journal. >=20 > Apart from that (which needs to be fixed by adding a field to the > struct bio), we believe the code to be quite stable now, so future > work will be mainly focused on adding more scheduling algorithms > and doing a thorough performance evaluation under various workloads. > In the meantime we'd really appreciate any comment from you on the > approach we took, and anyone testing the code. Hi, Do you have some documentation about the long-term plans? You will have to add an additional field to bio, of course, but there is one more thing: the schedulers will have to be integrated into the GEOM in an "invisible" way. I.e. instead of /dev/ad0-sched-s1f the users should see only /dev/ad0 like they're used to, and get the schedulers by default. Otherwise, your work will not get much use. This is not the only case where "invisible" classes are needed. Back when I was working on GEOM logging (what has since turned into gjournal), there was also a need to be able to insert a class transparently in between two classes in a tree without disturbing either (so for example you could turn IO request logging if needed on a "hot" server). IIRC Pawel had some similar needs and maybe some ideas but I don't know much there. I've CC-ed freebsd-geom@ so the discussion can get more technical there := ) --------------enig8F0B0F8DA61062B1221FE939 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAkm0EKYACgkQldnAQVacBcimfQCdEsqsvMDMz9FuH2V15KDEEudl xBwAoIUAG2RgfYeHZvyjEPV32N2mpY34 =pk+/ -----END PGP SIGNATURE----- --------------enig8F0B0F8DA61062B1221FE939--