From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-4.0 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI shortcircuit=no autolearn=ham autolearn_force=no version=3.4.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id 498F41F954 for ; Tue, 21 Aug 2018 19:54:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726808AbeHUXPh (ORCPT ); Tue, 21 Aug 2018 19:15:37 -0400 Received: from cloud.peff.net ([104.130.231.41]:50890 "HELO cloud.peff.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1726730AbeHUXPh (ORCPT ); Tue, 21 Aug 2018 19:15:37 -0400 Received: (qmail 8776 invoked by uid 109); 21 Aug 2018 19:54:06 -0000 Received: from Unknown (HELO peff.net) (10.0.1.2) by cloud.peff.net (qpsmtpd/0.94) with SMTP; Tue, 21 Aug 2018 19:54:06 +0000 Authentication-Results: cloud.peff.net; auth=none Received: (qmail 26555 invoked by uid 111); 21 Aug 2018 19:54:11 -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; Tue, 21 Aug 2018 15:54:11 -0400 Authentication-Results: peff.net; auth=none Received: by sigill.intra.peff.net (sSMTP sendmail emulation); Tue, 21 Aug 2018 15:54:04 -0400 Date: Tue, 21 Aug 2018 15:54:04 -0400 From: Jeff King To: Derrick Stolee Cc: git@vger.kernel.org Subject: Re: [PATCH 5/6] pack-bitmap: save "have" bitmap from walk Message-ID: <20180821195403.GC859@sigill.intra.peff.net> References: <20180821184140.GA24165@sigill.intra.peff.net> <20180821190701.GE30764@sigill.intra.peff.net> <7dadd117-e7f4-4d15-b907-043718022494@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <7dadd117-e7f4-4d15-b907-043718022494@gmail.com> Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Tue, Aug 21, 2018 at 03:47:36PM -0400, Derrick Stolee wrote: > On 8/21/2018 3:07 PM, Jeff King wrote: > > When we do a bitmap walk, we save the result, which > > represents (WANTs & ~HAVEs); i.e., every object we care > > about visiting in our walk. However, we throw away the > > haves bitmap, which can sometimes be useful, too. Save it > > and provide an access function so code which has performed a > > walk can query it. > > This makes a lot of sense. Based on the amount of time the "Counting > Objects" blog post [1] spent talking about delta bases, I would have assumed > this "haves" bitmap was already part of it. But, I can also see how it could > be dropped if you are focusing on performance for 'git clone'. I think that blog post was written after we were already using this patch. ;) > > A few notes on the accessor interface: > > > > - the bitmap code calls these "haves" because it grew out > > of the want/have negotiation for fetches. But really, > > these are simply the objects that would be flagged > > UNINTERESTING in a regular traversal. Let's use that > > more universal nomenclature for the external module > > interface. We may want to change the internal naming > > inside the bitmap code, but that's outside the scope of > > this patch. > > I saw the uninteresting-vs-haves name confusion in the patch below, but I > agree with your logic here. > > Sorry that I'm late to the party, but I was interested in the topic. This has already missed the freeze for v2.19, so I think there is plenty of time. More review would be welcome. -Peff