From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Torvalds Subject: Re: pack operation is thrashing my server Date: Thu, 14 Aug 2008 17:06:13 -0700 (PDT) Message-ID: References: <20080813145944.GB3782@spearce.org> <20080813155016.GD3782@spearce.org> <20080814233958.GA31225@atjola.homenet> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Nicolas Pitre , "Shawn O. Pearce" , Geert Bosch , Andi Kleen , Ken Pratt , git@vger.kernel.org To: =?ISO-8859-15?Q?Bj=F6rn_Steinbrink?= X-From: git-owner@vger.kernel.org Fri Aug 15 02:08:10 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 1KTmrS-0005Fe-4P for gcvg-git-2@gmane.org; Fri, 15 Aug 2008 02:08:10 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752277AbYHOAHE convert rfc822-to-quoted-printable (ORCPT ); Thu, 14 Aug 2008 20:07:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752282AbYHOAHD (ORCPT ); Thu, 14 Aug 2008 20:07:03 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:38663 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752225AbYHOAHB (ORCPT ); Thu, 14 Aug 2008 20:07:01 -0400 Received: from imap1.linux-foundation.org (imap1.linux-foundation.org [140.211.169.55]) by smtp1.linux-foundation.org (8.14.2/8.13.5/Debian-3ubuntu1.1) with ESMTP id m7F06EnD032172 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 14 Aug 2008 17:06:16 -0700 Received: from localhost (localhost [127.0.0.1]) by imap1.linux-foundation.org (8.13.5.20060308/8.13.5/Debian-3ubuntu1.1) with ESMTP id m7F06Dfs004446; Thu, 14 Aug 2008 17:06:14 -0700 In-Reply-To: <20080814233958.GA31225@atjola.homenet> User-Agent: Alpine 1.10 (LFD 962 2008-03-14) X-Spam-Status: No, hits=-3.413 required=5 tests=AWL,BAYES_00 X-Spam-Checker-Version: SpamAssassin 3.2.4-osdl_revision__1.47__ X-MIMEDefang-Filter: lf$Revision: 1.188 $ X-Scanned-By: MIMEDefang 2.63 on 140.211.169.13 Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: On Fri, 15 Aug 2008, Bj=F6rn Steinbrink wrote: >=20 > Since you mention the delta cache, uau (no idea about his real name) = on > #git was talking about some delta cache optimizations lately, althoug= h > he was dealing with "git log -S", maybe it affects rev-list in a simi= lar > way. Unfortunately, I can't seem to find any code for that, just a > description of what he did and some numbers on the results in the IRC > logs. Yes, interesting. The delta cache was really a huge hack that just turned out rather=20 successful. It's been hacked on further since (to do some half-way=20 reasonable replacement with _another_ hack by adding an LRU on top of i= t),=20 but it really is very hacky indeed. The "hash" we use for looking things up is also pretty much a joke, and= it=20 has no overflow capability, it just replaces the old entry with a new o= ne. I wonder how hard it would be to replace the whole table thing with our= =20 generic hash.c hash thing. I'll take a look. Linus