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=-3.8 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 249E81F46C for ; Tue, 21 Jan 2020 20:07:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727523AbgAUUHe (ORCPT ); Tue, 21 Jan 2020 15:07:34 -0500 Received: from mail-ot1-f67.google.com ([209.85.210.67]:35055 "EHLO mail-ot1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726926AbgAUUHe (ORCPT ); Tue, 21 Jan 2020 15:07:34 -0500 Received: by mail-ot1-f67.google.com with SMTP id i15so4164670oto.2 for ; Tue, 21 Jan 2020 12:07:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=0njAnNw2saITtkJ02uCNp675VMngnT5QANgfDJVAkEM=; b=KZBVAvWNcO/l6d4EjPVNwt3/+WIsQIEwDyQCcX2u2zPpEflEa6rXZgABDSeCaPIStn ufmqV+F1c69n+JVNXi+S3xaDKjLVkIAuaMRef7wjY/2mSZo2a8uCy/Q5WRN54p6CbxcE IDoRhhCoMxFIMjiZKqUVZMlFlmK4Nr+7HoghqDUPm6h4CBHXOyJ4FSu2+GLuqsd3TVQP o2Zw0oBM/VurI4iVrI6Nus6jK2xFuvrauBfcA0y+29dA98kAkDTcWr5HmLSfWAOdfOtl lQp2u6nuaZyB42SZi8NMgeLjt8VTSWuw1lwIG7kJbP/CqL8E4vQ4oYGTsiRUo0JXl00u c97A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=0njAnNw2saITtkJ02uCNp675VMngnT5QANgfDJVAkEM=; b=j59ainwW522TbhMamnU4YjOMdSNpFYP5iQ8uk5tiisbuLhBc6it+yErEgXFig9KNlC SFAdfQFUyA+8zRSS02G3d1qdTZgxdBCXQub5TYRO6VDw9EmZL7WebaW9cxZprAy4eDng hP3iLxY8Ulz+zcnDgPc6KICtvCDdrNVzt23q8OuC5x1Gt6pXuJ8RFNf/V2tr3ntl4UMA x5FZ3RZWh6xrowHIfhwjCEl39F25GvnpCXFFvQVPMIEK0yqbGncGIhVNgjnDTHp64RsO Qw+8hv5zqTPsM8PO/QSUg9zl2qYcKgnlhoXzIJSFhK5TVVPmFago4Hk7vd3e/0GgWDdb vgxQ== X-Gm-Message-State: APjAAAV93hrWbcvhjpglrfPaRPuWcNyf72/xG12UqehUr20QINMyqXxs ozYSRGpmysSVuk1TZHCDJJkoxfT9XjrHuL0MPkGzI30a X-Google-Smtp-Source: APXvYqxPoikAOGndeudq6t/pxjRL7I74ragFQL5W+79Z+hG9og6PVDyYCcGwGPIW6NBoRLBq8tBG+WYIC1UUqAaix8c= X-Received: by 2002:a9d:24ea:: with SMTP id z97mr4907557ota.345.1579637252547; Tue, 21 Jan 2020 12:07:32 -0800 (PST) MIME-Version: 1.0 References: <20200109150332.GF32750@szeder.dev> <20200121191857.23047-1-alban.gruin@gmail.com> In-Reply-To: <20200121191857.23047-1-alban.gruin@gmail.com> From: Elijah Newren Date: Tue, 21 Jan 2020 12:07:20 -0800 Message-ID: Subject: Re: [PATCH v1] rebase -i: stop checking out the tip of the branch to rebase To: Alban Gruin Cc: =?UTF-8?Q?SZEDER_G=C3=A1bor?= , Git Mailing List , =?UTF-8?B?w4Z2YXIgQXJuZmrDtnLDsA==?= , Eugeniu Rosca , Junio C Hamano , Jeff King , Eugeniu Rosca , Phillip Wood , Johannes Schindelin Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Hi Alban, // Adding Phillip and Johannes since they know the sequencer internals very well. On Tue, Jan 21, 2020 at 11:21 AM Alban Gruin wrote: > > One of the first things done by the interactive rebase is to make a todo > list. This requires knowledge of the commit range to rebase. To get > the oid of the last commit of the range, the tip of the branch to rebase > is checked out with prepare_branch_to_be_rebased(), then the oid of the > HEAD is read. On big repositories, it's a performance penalty: the user > may have to wait before editing the todo list while git is extracting the > branch silently (because git-checkout is silenced here). After this, > the head of the branch is not even modified. > > Since we already have the oid of the tip of the branch in > `opts->orig_head', it's useless to switch to this commit. > > This removes the call to prepare_branch_to_be_rebased() in > do_interactive_rebase(), and adds a `orig_head' parameter to > get_revision_ranges(). prepare_branch_to_be_rebased() is removed as it > is no longer used. > > This introduces a visible change: as we do not switch on the tip of the > branch to rebase, no reflog entry is created at the beginning of the > rebase for it. Oh, sweet, thanks for digging in. I had also dug in just after the report, but not quite far enough as I still had failing tests and I was feeling a bit stretched thin on other projects so I punted hoping that SZEDER would post something. Looks like the orig_head thing was probably what I was missing. I was a little surprised that there wasn't any regression test that needed to be modified, as it reminded me of a previous conversation about excessive work in the interactive backend[1], but after looking it up that was apparently about too many calls to commit rather than too many calls to checkout. [1] https://lore.kernel.org/git/nycvar.QRO.7.76.6.1811121614190.39@tvgsbejv= aqbjf.bet/ > Reported-by: SZEDER G=C3=A1bor > Signed-off-by: Alban Gruin > --- > > Notes: > Improvements brought by this patch: > > Before: > > $ time git rebase -m --onto v4.18 463fa44eec2fef50~ 463fa44eec2fef50 > > real 0m8,940s > user 0m6,830s > sys 0m2,121s > > After: > > $ time git rebase -m --onto v4.18 463fa44eec2fef50~ 463fa44eec2fef50 > > real 0m1,834s > user 0m0,916s > sys 0m0,206s Nice...do we want to mention this in the commit message proper too? > > Both tests have been performed on a 5400 RPM SATA III hard drive. > > builtin/rebase.c | 18 +++++------------- > sequencer.c | 14 -------------- > sequencer.h | 3 --- > 3 files changed, 5 insertions(+), 30 deletions(-) > > diff --git a/builtin/rebase.c b/builtin/rebase.c > index 8081741f8a..6154ad8fa5 100644 > --- a/builtin/rebase.c > +++ b/builtin/rebase.c > @@ -246,21 +246,17 @@ static int edit_todo_file(unsigned flags) > } > > static int get_revision_ranges(struct commit *upstream, struct commit *o= nto, > - const char **head_hash, > + struct object_id *orig_head, const char **= head_hash, > char **revisions, char **shortrevisions) > { > struct commit *base_rev =3D upstream ? upstream : onto; > const char *shorthead; > - struct object_id orig_head; > - > - if (get_oid("HEAD", &orig_head)) > - return error(_("no HEAD?")); > > - *head_hash =3D find_unique_abbrev(&orig_head, GIT_MAX_HEXSZ); > + *head_hash =3D find_unique_abbrev(orig_head, GIT_MAX_HEXSZ); > *revisions =3D xstrfmt("%s...%s", oid_to_hex(&base_rev->object.oi= d), > *head_hash); > > - shorthead =3D find_unique_abbrev(&orig_head, DEFAULT_ABBREV); > + shorthead =3D find_unique_abbrev(orig_head, DEFAULT_ABBREV); > > if (upstream) { > const char *shortrev; > @@ -314,12 +310,8 @@ static int do_interactive_rebase(struct rebase_optio= ns *opts, unsigned flags) > struct replay_opts replay =3D get_replay_opts(opts); > struct string_list commands =3D STRING_LIST_INIT_DUP; > > - if (prepare_branch_to_be_rebased(the_repository, &replay, > - opts->switch_to)) > - return -1; > - > - if (get_revision_ranges(opts->upstream, opts->onto, &head_hash, > - &revisions, &shortrevisions)) > + if (get_revision_ranges(opts->upstream, opts->onto, &opts->orig_h= ead, > + &head_hash, &revisions, &shortrevisions)) > return -1; > > if (init_basic_state(&replay, > diff --git a/sequencer.c b/sequencer.c > index b9dbf1adb0..4dc245d7ec 100644 > --- a/sequencer.c > +++ b/sequencer.c > @@ -3715,20 +3715,6 @@ static int run_git_checkout(struct repository *r, = struct replay_opts *opts, > return ret; > } > > -int prepare_branch_to_be_rebased(struct repository *r, struct replay_opt= s *opts, > - const char *commit) > -{ > - const char *action; > - > - if (commit && *commit) { > - action =3D reflog_message(opts, "start", "checkout %s", c= ommit); > - if (run_git_checkout(r, opts, commit, action)) > - return error(_("could not checkout %s"), commit); > - } > - > - return 0; > -} > - > static int checkout_onto(struct repository *r, struct replay_opts *opts, > const char *onto_name, const struct object_id *o= nto, > const char *orig_head) > diff --git a/sequencer.h b/sequencer.h > index 9f9ae291e3..74f1e2673e 100644 > --- a/sequencer.h > +++ b/sequencer.h > @@ -190,9 +190,6 @@ void commit_post_rewrite(struct repository *r, > const struct commit *current_head, > const struct object_id *new_head); > > -int prepare_branch_to_be_rebased(struct repository *r, struct replay_opt= s *opts, > - const char *commit); > - > #define SUMMARY_INITIAL_COMMIT (1 << 0) > #define SUMMARY_SHOW_AUTHOR_DATE (1 << 1) > void print_commit_summary(struct repository *repo, > -- > 2.24.1 The code looks reasonable to me, but I'm still not completely familiar with all the rebase and sequencer code so I'm hoping Phillip or Johannes can give a thumbs up. Thanks for digging into this and figuring out the bits that I missed when I tried. Elijah