From mboxrd@z Thu Jan 1 00:00:00 1970 From: A Large Angry SCM Subject: Re: [PATCH 0/5] Suggested for PU: revision caching system to significantly speed up packing/walking Date: Thu, 06 Aug 2009 19:35:32 -0400 Message-ID: <4A7B68C4.8070406@gmail.com> References: <4A7AEFA8.5010001@drmicha.warpmail.net> <20090806203223.GK1033@spearce.org> Reply-To: gitzilla@gmail.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Nick Edelen , Johannes Schindelin , Michael J Gruber , Junio C Hamano , Jeff King , Sam Vilain , Andreas Ericsson , Christian Couder , "git@vger.kernel.org" To: "Shawn O. Pearce" X-From: git-owner@vger.kernel.org Fri Aug 07 01:36:09 2009 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 1MZCVD-0000ZH-1F for gcvg-git-2@gmane.org; Fri, 07 Aug 2009 01:36:07 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756569AbZHFXfl (ORCPT ); Thu, 6 Aug 2009 19:35:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755967AbZHFXfl (ORCPT ); Thu, 6 Aug 2009 19:35:41 -0400 Received: from mail-yw0-f177.google.com ([209.85.211.177]:57948 "EHLO mail-yw0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752015AbZHFXfk (ORCPT ); Thu, 6 Aug 2009 19:35:40 -0400 Received: by ywh7 with SMTP id 7so1633491ywh.21 for ; Thu, 06 Aug 2009 16:35:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id :disposition-notification-to:date:from:reply-to:user-agent :mime-version:to:cc:subject:references:in-reply-to:content-type :content-transfer-encoding; bh=G5GGKOzMQ3B+ZiEjCOqHeGNe0s5XAfdcRLJHoF353Og=; b=b2oWAVM/T+K+mttqsIorWA1DOOZ1lUgNr2nMdoOptVk7Ltc1WTzx60Zdr2oOH5gyhK IYp6LTAZL4K7Gxw/M1V/CP4OEEdeozcgDqNcYoAkl3QXT73HdtksuNixUjBh7l9EOXwd tv8wUTXMkrOV1x/ToVVWoviEzgz5wZb23JcU4= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:disposition-notification-to:date:from:reply-to :user-agent:mime-version:to:cc:subject:references:in-reply-to :content-type:content-transfer-encoding; b=l6HOk2qosqQ5iqc4+VpA3f2RN/PQLXZNDIoUaNygf8EIf+nkSsA0fRRddmxQbPo5sC yAuP6P8rqXXMLk2j9S0oRX1HE2yl66XJcO9h02cjMTh9FGsZ/WWyHkBmbEqDYxFrDjcW mzWZ5/bP01Ggnz/5np7zf5JS23+TkOUqjrGrU= Received: by 10.90.75.9 with SMTP id x9mr350251aga.71.1249601739954; Thu, 06 Aug 2009 16:35:39 -0700 (PDT) Received: from ?10.0.0.6? (c-71-199-240-201.hsd1.fl.comcast.net [71.199.240.201]) by mx.google.com with ESMTPS id 20sm1200808agb.75.2009.08.06.16.35.38 (version=TLSv1/SSLv3 cipher=RC4-MD5); Thu, 06 Aug 2009 16:35:39 -0700 (PDT) User-Agent: Thunderbird 1.5.0.10 (X11/20060911) In-Reply-To: <20090806203223.GK1033@spearce.org> Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: Shawn O. Pearce wrote: > Nick Edelen wrote: >> Hrmm, I just realized that it dosn't actually cache paths/names... >> This obviously has no bearing on its use in packing, but I should >> either add that in or restrict usage in non-packing-related walks. >> Weird how things like that escape you. >> >> I think I may go ahead and add support for this tomorrow. It should >> have no effect on performance and very little impact on cache slice >> size. > > You may not need the path name, but instead the hash value that > pack-objects computes from the path name. All that matters is > the hash, so pack-objects can schedule the objects into the right > buckets when its doing delta computation for objects which are not > yet delta compressed, or whose delta cannot be suitably reused. > Please do NOT expose the hash values. The hash used by pack-objects is an implementation detail of the heuristics used by the _current_ object packing code. It would be a real shame to have to maintain backward compatibility with it at some future date after the packing machinery has changed.