From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-3.9 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI,RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE, SPF_NONE shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id 627431F487 for ; Fri, 27 Mar 2020 15:04:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727803AbgC0PED (ORCPT ); Fri, 27 Mar 2020 11:04:03 -0400 Received: from mail-pf1-f193.google.com ([209.85.210.193]:41814 "EHLO mail-pf1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727726AbgC0PED (ORCPT ); Fri, 27 Mar 2020 11:04:03 -0400 Received: by mail-pf1-f193.google.com with SMTP id z65so4624986pfz.8 for ; Fri, 27 Mar 2020 08:04:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ttaylorr-com.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=OJRA+WxtWwHNbNSVepFr7HQ9MMLN6vmu3FwE4vCW2Bw=; b=To2ngMZ9mnq4KXQLtN42L3DEHt5D0ujSfo2sdQN0FrL4nAPewFwpDD3K4NK7LLDIy/ qlC4POxqMn4rs6e+DipNEh5z7HNxfsOHfH24Rvqn+NBxHuHAWarJtW8bel5Y6zHCsZNX M6SAh0wWaNuqZVgB9fewjcfeFJk4b3Mkdi8QKB05MNtb/PT+RTJsWCEjvM/ah3M17Ikw gLmBIuLJxSYPB8ujbR9g+0H0rU9s19ST0l3DH5Oz8G4iPhAGFg4BLRImoIJtmRRPQAT8 OeDtRPC1VLWN+9E+ocYwZ8h7vCjMvhWkSt40PVaxwdGUNugQDvXI3GWjQ8kZMFQDmtNA LaMQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=OJRA+WxtWwHNbNSVepFr7HQ9MMLN6vmu3FwE4vCW2Bw=; b=AQwRLWez8dZ2hXiHiR8O/OF/USU/h4PxTPE6QOJTWaBFlE+aHhSTc5h5z8MEB69ry7 qFECgo6jue6BTpP0yxKJfJJtidoaO9FZwYg4ULsdqFXDhJjRx3JKhwlOAKMdMawaj0VL F4Jjz7G4L5E4fnDyN+PNgI8sN+hCrz8gDW+iDc8Eol1C0MTy40WCXtjT3Fm8mK3Z/QVf l7M7wGA8tiPBlYE0TRkwBfPSiA/4JY+L5OaKk84pxeOIogp1CYP0GnPRxmu78qiexjUq dh6BFIAaIe/bQYAsxYq/ht+cnmK+JBKI1NI72FyF4yyp8nuxs6OJzAmXmt2u8uCCyrHD OXvw== X-Gm-Message-State: ANhLgQ26RdAA8UolLt9Id1abo2bsar/TNB2/p/1NbIh9kCripfHol69O Wj4x2VeNgDIal6k8zMEzlFtEiQ== X-Google-Smtp-Source: ADFU+vszkUbqmOwUSIXtm5VLdCKB4oX1/e4Ra30gh90gHoIohdq63QIx56tQSB5mV7npIQtJE/SaGA== X-Received: by 2002:a63:b52:: with SMTP id a18mr1719249pgl.130.1585321441078; Fri, 27 Mar 2020 08:04:01 -0700 (PDT) Received: from localhost ([8.44.146.30]) by smtp.gmail.com with ESMTPSA id f22sm4047197pgl.20.2020.03.27.08.03.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 27 Mar 2020 08:03:59 -0700 (PDT) Date: Fri, 27 Mar 2020 09:03:58 -0600 From: Taylor Blau To: Jeff King Cc: Taylor Blau , Derrick Stolee , Junio C Hamano , git@vger.kernel.org, dstolee@microsoft.com Subject: Re: [PATCH 1/1] commit-graph.c: avoid unnecessary tag dereference when merging Message-ID: <20200327150358.GA30204@syl.local> References: <20200322002005.GA48038@syl.local> <1cb561fc-5bce-28f0-e5e1-886f590fba92@gmail.com> <20200322054916.GB578498@coredump.intra.peff.net> <20200322060434.GC578498@coredump.intra.peff.net> <20200322154749.GB53402@syl.local> <20200324061159.GC610977@coredump.intra.peff.net> <20200324230826.GA42939@syl.local> <20200327084248.GA607390@coredump.intra.peff.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200327084248.GA607390@coredump.intra.peff.net> User-Agent: Mutt/1.11.4 (2019-03-13) Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Fri, Mar 27, 2020 at 04:42:48AM -0400, Jeff King wrote: > On Tue, Mar 24, 2020 at 05:08:26PM -0600, Taylor Blau wrote: > > I can plan to deploy this patch to GitHub's servers for a ~month and > > see if we experience it. > > ...I don't think we'll actually generate good data here. We're probably > going to end up doing our "big maintenance" commit-graph roll-ups by > just feeding --reachable as input, and dropping all of the existing > graphs. For what it's worth (and I'm not sure that it's worth much), but this is only true in the last day or so. Before, we were running: $ git commit-graph write --split=merge-all --input=none which *did* exercise this code quite frequently (and thus would have been helped by this patch). But now, we are running something like: $ git commit-graph write --split=replace --input=reachable ...where '--split=replace' means "write a split commit-graph, but drop all existing layers before writing it". This case is obviously not helped by this patch, although I think the patch is worthwhile for callers who do the first thing. I'll post patches about that shortly after they've been a little more well-vetted (we're only generating split commit-graphs on a percentage of repositories for now). > -Peff Thanks, Taylor