From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-3.6 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_HI,T_RP_MATCHES_RCVD shortcircuit=no autolearn=ham autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id 9F4F41F404 for ; Thu, 25 Jan 2018 00:10:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932300AbeAYAKS (ORCPT ); Wed, 24 Jan 2018 19:10:18 -0500 Received: from cloud.peff.net ([104.130.231.41]:56498 "HELO cloud.peff.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S932293AbeAYAKR (ORCPT ); Wed, 24 Jan 2018 19:10:17 -0500 Received: (qmail 16291 invoked by uid 109); 25 Jan 2018 00:10:18 -0000 Received: from Unknown (HELO peff.net) (10.0.1.2) by cloud.peff.net (qpsmtpd/0.94) with SMTP; Thu, 25 Jan 2018 00:10:18 +0000 Authentication-Results: cloud.peff.net; auth=none Received: (qmail 31240 invoked by uid 111); 25 Jan 2018 00:10:55 -0000 Received: from sigill.intra.peff.net (HELO sigill.intra.peff.net) (10.0.0.7) by peff.net (qpsmtpd/0.94) with (ECDHE-RSA-AES256-GCM-SHA384 encrypted) SMTP; Wed, 24 Jan 2018 19:10:55 -0500 Authentication-Results: peff.net; auth=none Received: by sigill.intra.peff.net (sSMTP sendmail emulation); Wed, 24 Jan 2018 19:10:15 -0500 Date: Wed, 24 Jan 2018 19:10:15 -0500 From: Jeff King To: =?utf-8?B?w4Z2YXIgQXJuZmrDtnLDsA==?= Bjarmason Cc: Git mailing list , Junio C Hamano Subject: Re: Git packs friendly to block-level deduplication Message-ID: <20180125001015.GA17856@sigill.intra.peff.net> References: <87bmhiykvw.fsf@evledraar.gmail.com> <20180124232214.GA11348@sigill.intra.peff.net> <87607qyfci.fsf@evledraar.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <87607qyfci.fsf@evledraar.gmail.com> Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Thu, Jan 25, 2018 at 01:03:25AM +0100, Ævar Arnfjörð Bjarmason wrote: > > You may also want to use "--threads=1" to avoid non-determinism in the > > generated packs. In theory, both repos would then produce identical base > > packs, though it does not seem to do so in practice (I didn't dig in to > > what the different may be). > > ..and north of 20% with --threads=1. > > [...] > > Thanks. I'll look into that, although the above results (sans hacking on > the core pack-objects logic) suggest that even once I create an island > I'm getting at most 20%. I think it may be worth figuring out where the two differ. With --no-reuse-object and --no-reuse-delta, I'd think that the pack generated for a particular apex commit would be totally deterministic, regardless of other objects available in the repo. But it's not for some reason. -Peff