From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff King Subject: Re: [PATCH 4/6] introduce a commit metapack Date: Fri, 1 Feb 2013 05:40:10 -0500 Message-ID: <20130201104010.GH30644@sigill.intra.peff.net> References: <20130129091434.GA6975@sigill.intra.peff.net> <20130129091610.GD9999@sigill.intra.peff.net> <20130130135607.GA23154@lanh> <20130131110656.GA28093@lanh> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Cc: git@vger.kernel.org, "Shawn O. Pearce" To: Duy Nguyen X-From: git-owner@vger.kernel.org Fri Feb 01 11:40:43 2013 Return-path: Envelope-to: gcvg-git-2@plane.gmane.org Received: from vger.kernel.org ([209.132.180.67]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1U1E2u-0002sA-VN for gcvg-git-2@plane.gmane.org; Fri, 01 Feb 2013 11:40:37 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756016Ab3BAKkP (ORCPT ); Fri, 1 Feb 2013 05:40:15 -0500 Received: from 75-15-5-89.uvs.iplsin.sbcglobal.net ([75.15.5.89]:55376 "EHLO peff.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754980Ab3BAKkO (ORCPT ); Fri, 1 Feb 2013 05:40:14 -0500 Received: (qmail 28075 invoked by uid 107); 1 Feb 2013 10:41:37 -0000 Received: from c-71-206-173-132.hsd1.va.comcast.net (HELO sigill.intra.peff.net) (71.206.173.132) (smtp-auth username relayok, mechanism cram-md5) by peff.net (qpsmtpd/0.84) with ESMTPA; Fri, 01 Feb 2013 05:41:37 -0500 Received: by sigill.intra.peff.net (sSMTP sendmail emulation); Fri, 01 Feb 2013 05:40:10 -0500 Content-Disposition: inline In-Reply-To: <20130131110656.GA28093@lanh> Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: On Thu, Jan 31, 2013 at 06:06:56PM +0700, Nguyen Thai Ngoc Duy wrote: > On Wed, Jan 30, 2013 at 09:16:29PM +0700, Duy Nguyen wrote: > > Perhaps we could store abbrev sha-1 instead of full sha-1. Nice > > space/time trade-off. > > Following the on-disk format experiment yesterday, I changed the > format to: > > - a list a _short_ SHA-1 of cached commits > - a list of cache entries, each (5 uint32_t) consists of: > - uint32_t for the index in .idx sha-1 table to get full SHA-1 of > the commit > - uint32_t for timestamp > - uint32_t for tree, 1st and 2nd parents for the index in .idx > table BTW, I needed the minor fixups below to silence some warnings from your patch. Here are the cold and warm cache timings I got, as compared to stock git and my implementation: Pack | Cold Revs | Warm Revs -------+--------------+------------ stock | 12.54 | 4.14 me | 4.76 (-62%) | 0.66 (-84%) duy | 4.36 (-65%) | 0.55 (-86%) Not surprising; yours is just a bit faster in terms of CPU, and even gains a little more in the cold cache case. Nice. Of course that is just gravy on top of the smaller disk usage, too. :) --- diff --git a/commit-metapack.c b/commit-metapack.c index c984b8e..78fd961 100644 --- a/commit-metapack.c +++ b/commit-metapack.c @@ -106,7 +106,7 @@ int commit_metapack(unsigned char *sha1, for (p = commit_metapacks; p; p = p->next) { struct commit_entry *data; uint32_t p1, p2; - unsigned lo, hi, mi; + unsigned lo, hi; int pos; /* sha1_entry_pos does not work with abbreviated sha-1 */ @@ -161,7 +161,7 @@ static void get_commits(struct metapack_writer *mw, struct write_cb *write_cb = (struct write_cb *)data; enum object_type type = sha1_object_info(sha1, NULL); struct commit *c; - int p1, p2; + int p1 = -1, p2 = -1; if (type != OBJ_COMMIT) return; diff --git a/commit.c b/commit.c index b326201..5b776f8 100644 --- a/commit.c +++ b/commit.c @@ -309,7 +309,7 @@ static int parse_commit_metapack(struct commit *item) static int parse_commit_metapack(struct commit *item) { - unsigned char *tree, *p1, *p2; + const unsigned char *tree, *p1, *p2; uint32_t ts; if (commit_metapack(item->object.sha1, &ts, &tree, &p1, &p2) < 0)