From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre Habouzit Subject: Re: [PATCH WIP] sha1-lookup: make selection of 'middle' less aggressive Date: Tue, 01 Jan 2008 15:51:30 +0100 Message-ID: <20080101145130.GD3893@artemis.madism.org> References: <7vd4soa3cw.fsf@gitster.siamese.dyndns.org> <7vtzm08l9w.fsf@gitster.siamese.dyndns.org> <7vodc77t0o.fsf@gitster.siamese.dyndns.org> <20080101063616.GA21605@coredump.intra.peff.net> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="UfEAyuTBtIjiZzX6"; protocol="application/pgp-signature"; micalg=SHA1 Cc: Linus Torvalds , Marco Costalba , Junio C Hamano , git@vger.kernel.org To: Jeff King X-From: git-owner@vger.kernel.org Tue Jan 01 15:52:05 2008 Return-path: Envelope-to: gcvg-git-2@gmane.org Received: from vger.kernel.org ([209.132.176.167]) by lo.gmane.org with esmtp (Exim 4.50) id 1J9iTM-0004E3-Dc for gcvg-git-2@gmane.org; Tue, 01 Jan 2008 15:52:04 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752313AbYAAOve (ORCPT ); Tue, 1 Jan 2008 09:51:34 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752290AbYAAOvd (ORCPT ); Tue, 1 Jan 2008 09:51:33 -0500 Received: from pan.madism.org ([88.191.52.104]:43105 "EHLO hermes.madism.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752216AbYAAOvc (ORCPT ); Tue, 1 Jan 2008 09:51:32 -0500 Received: from madism.org (unknown [82.236.23.208]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "artemis.madism.org", Issuer "madism.org" (not verified)) by hermes.madism.org (Postfix) with ESMTP id A77E520FA0; Tue, 1 Jan 2008 15:51:30 +0100 (CET) Received: by madism.org (Postfix, from userid 1000) id 300D23388; Tue, 1 Jan 2008 15:51:30 +0100 (CET) Mail-Followup-To: Pierre Habouzit , Jeff King , Linus Torvalds , Marco Costalba , Junio C Hamano , git@vger.kernel.org Content-Disposition: inline In-Reply-To: <20080101063616.GA21605@coredump.intra.peff.net> X-Face: $(^e[V4D-[`f2EmMGz@fgWK!e.B~2g.{08lKPU(nc1J~z\4B>*JEVq:E]7G-\6$Ycr4<;Z!|VY6Grt]+RsS$IMV)f>2)M="tY:ZPcU;&%it2D81X^kNya0=L]"vZmLP+UmKhgq+u*\.dJ8G!N&=EvlD User-Agent: Madmutt/devel (Linux) Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: --UfEAyuTBtIjiZzX6 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Jan 01, 2008 at 06:36:16AM +0000, Jeff King wrote: > zlib makes a noticeable impact in real world cases. On a git.git repo, > fully packed with stock config, warm cache: On linux-2.6.git, with compressed packs: $ =3Dtime git whatchanged >|/dev/null 19.67user 1.24system 0:21.01elapsed 99%CPU (0avgtext+0avgdata 0maxresid= ent)k 0inputs+0outputs (0major+38556minor)pagefaults 0swaps Without compression: $ =3Dtime git whatchanged >|/dev/null 14.41user 1.23system 0:15.67elapsed 99%CPU (0avgtext+0avgdata 0maxresid= ent)k 0inputs+0outputs (0major+44678minor)pagefaults 0swaps > More pagefaults, but a 25% improvement in wall clock time. The packfile > is noticeably larger (55M versus 40M), so I'm sure the cold cache case > sucks. It may also change with larger repos, where the packfile size > difference kills your cache. The packfile is _incredibly_ larger (~200Mo -> ~420, though I suppose the first one was packed with a larger window, coming from kernel.org). I experience the same 25% wall clock reduction here as well. Though, even if larger, linux-2.6.git still stays in RAM easily on my machine. On an unrelated note, I wonder if it wouldn't be possible for git at fetch time to "share" a very efficient pack that was computed on some host. I mean, if I'm not mistaken, at clone time you get the efficient pack, but at fetch time only incremental parts. I wonder if there would be ways to say "hey, we recomputed here a very very very good pack, take it instead of yours. --=20 =C2=B7O=C2=B7 Pierre Habouzit =C2=B7=C2=B7O madcoder@debia= n.org OOO http://www.madism.org --UfEAyuTBtIjiZzX6 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQBHelNyvGr7W6HudhwRAlosAJ9Dsd9Bdg1+ORUxmSfEpbZis1iOTwCfY3TH spRJK1zAiSQeM8xCN5K9qEY= =iFvX -----END PGP SIGNATURE----- --UfEAyuTBtIjiZzX6--