From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Torvalds Subject: Re: git performance Date: Fri, 24 Oct 2008 10:53:20 -0700 (PDT) Message-ID: References: <000901c93490$e0c40ed0$a24c2c70$@com> <20081023163912.GA11489@coredump.intra.peff.net> <000001c9358f$232bac70$69830550$@com> <20081024142947.GB11568@coredump.intra.peff.net> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: Edward Ned Harvey , git@vger.kernel.org To: Jeff King X-From: git-owner@vger.kernel.org Fri Oct 24 19:54:52 2008 connect(): Connection refused 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 1KtQs5-00075H-I3 for gcvg-git-2@gmane.org; Fri, 24 Oct 2008 19:54:50 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757639AbYJXRxj (ORCPT ); Fri, 24 Oct 2008 13:53:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757645AbYJXRxj (ORCPT ); Fri, 24 Oct 2008 13:53:39 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:36551 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752257AbYJXRxi (ORCPT ); Fri, 24 Oct 2008 13:53:38 -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 m9OHrLF5003095 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 24 Oct 2008 10:53:22 -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 m9OHrKcd010885; Fri, 24 Oct 2008 10:53:21 -0700 In-Reply-To: <20081024142947.GB11568@coredump.intra.peff.net> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) X-Spam-Status: No, hits=-3.443 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, 24 Oct 2008, Jeff King wrote: > > Side note: on Linux, it is much easier to clear the cache via > > echo 1 >/proc/sys/vm/drop_caches Use "echo 3" instead of "1". It's actually a bitmask, with bit 0 being "data" (pagecache) and bit 1 being "metadata" (inodes and directory caches). And since git (or any SCM) is very metadata-intensive, you really should make sure to drop metadata too, otherwise your caches won't be really very cold at all. (But it obviously depends on the operation you're testing - some are more about the inodes and directories, others are about file data access). Linus