From: Barret Rhoden <brho@google.com>
To: "René Scharfe" <l.s.r@web.de>, "Junio C Hamano" <gitster@pobox.com>
Cc: git@vger.kernel.org
Subject: Re: [PATCH 2/4] blame: validate and peel the object names on the ignore list
Date: Mon, 12 Oct 2020 16:39:33 -0400 [thread overview]
Message-ID: <cd2c51da-55c6-cc5e-2da1-69db90aaf438@google.com> (raw)
In-Reply-To: <1fa730c4-eaef-2f32-e1b4-716a27ed4646@web.de>
Hi -
On 10/11/20 12:03 PM, René Scharfe wrote:
[snip]
>> Any performance improvement would be welcome. I haven't looked at
>> the code in a while, but I don't recall any reasons why this wouldn't
>> work.
>
> Using a commit flag instead of an oidset would only improve
> performance noticeably if the product of the number of suspects and
> ignored commits was huge, I guess.
>
> I get weird timings for an ignore file containing basically all commits
> (created with "git log --format=%H"). With Git's own repo and rc1:
>
> Benchmark #1: ./git-blame --ignore-revs-file hashes Makefile
> Time (mean ± σ): 8.470 s ± 0.049 s [User: 7.923 s, System: 0.547 s]
> Range (min … max): 8.434 s … 8.605 s 10 runs
>
> And with the patch at the bottom:
>
> Benchmark #1: ./git-blame --ignore-revs-file hashes Makefile
> Time (mean ± σ): 8.048 s ± 0.061 s [User: 7.899 s, System: 0.146 s]
> Range (min … max): 7.987 s … 8.175 s 10 runs
>
> That looks like a nice speedup, but why for system time alone? Malloc
> overhead perhaps?
Hard to say. Maybe page faults when walking the old ignore_list?
> Anyway, here's the patch:
Looks good to me.
Barret
> ---
> blame.c | 2 +-
> blame.h | 5 +++--
> builtin/blame.c | 16 ++++++++++++----
> object.h | 3 ++-
> 4 files changed, 18 insertions(+), 8 deletions(-)
>
> diff --git a/blame.c b/blame.c
> index 686845b2b4..6e8c8fec9b 100644
> --- a/blame.c
> +++ b/blame.c
> @@ -2487,7 +2487,7 @@ static void pass_blame(struct blame_scoreboard *sb, struct blame_origin *origin,
> /*
> * Pass remaining suspects for ignored commits to their parents.
> */
> - if (oidset_contains(&sb->ignore_list, &commit->object.oid)) {
> + if (commit->object.flags & BLAME_IGNORE) {
> for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse);
> i < num_sg && sg;
> sg = sg->next, i++) {
> diff --git a/blame.h b/blame.h
> index b6bbee4147..d35167e8bd 100644
> --- a/blame.h
> +++ b/blame.h
> @@ -16,6 +16,9 @@
> #define BLAME_DEFAULT_MOVE_SCORE 20
> #define BLAME_DEFAULT_COPY_SCORE 40
>
> +/* Remember to update object flag allocation in object.h */
> +#define BLAME_IGNORE (1u<<14)
> +
> struct fingerprint;
>
> /*
> @@ -125,8 +128,6 @@ struct blame_scoreboard {
> /* linked list of blames */
> struct blame_entry *ent;
>
> - struct oidset ignore_list;
> -
> /* look-up a line in the final buffer */
> int num_lines;
> int *lineno;
> diff --git a/builtin/blame.c b/builtin/blame.c
> index bb0f29300e..1c6721b5d5 100644
> --- a/builtin/blame.c
> +++ b/builtin/blame.c
> @@ -830,21 +830,29 @@ static void build_ignorelist(struct blame_scoreboard *sb,
> {
> struct string_list_item *i;
> struct object_id oid;
> + const struct object_id *o;
> + struct oidset_iter iter;
> + struct oidset ignore_list = OIDSET_INIT;
>
> - oidset_init(&sb->ignore_list, 0);
> for_each_string_list_item(i, ignore_revs_file_list) {
> if (!strcmp(i->string, ""))
> - oidset_clear(&sb->ignore_list);
> + oidset_clear(&ignore_list);
> else
> - oidset_parse_file_carefully(&sb->ignore_list, i->string,
> + oidset_parse_file_carefully(&ignore_list, i->string,
> peel_to_commit_oid, sb);
> }
> for_each_string_list_item(i, ignore_rev_list) {
> if (get_oid_committish(i->string, &oid) ||
> peel_to_commit_oid(&oid, sb))
> die(_("cannot find revision %s to ignore"), i->string);
> - oidset_insert(&sb->ignore_list, &oid);
> + oidset_insert(&ignore_list, &oid);
> }
> + oidset_iter_init(&ignore_list, &iter);
> + while ((o = oidset_iter_next(&iter))) {
> + struct commit *commit = lookup_commit(sb->repo, o);
> + commit->object.flags |= BLAME_IGNORE;
> + }
> + oidset_clear(&ignore_list);
> }
>
> int cmd_blame(int argc, const char **argv, const char *prefix)
> diff --git a/object.h b/object.h
> index 20b18805f0..6818c9296b 100644
> --- a/object.h
> +++ b/object.h
> @@ -64,7 +64,8 @@ struct object_array {
> * negotiator/default.c: 2--5
> * walker.c: 0-2
> * upload-pack.c: 4 11-----14 16-----19
> - * builtin/blame.c: 12-13
> + * blame.c: 14
> + * builtin/blame.c: 12---14
> * bisect.c: 16
> * bundle.c: 16
> * http-push.c: 11-----14
> --
> 2.28.0
>
next prev parent reply other threads:[~2020-10-12 20:39 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-25 5:59 [PATCH 0/4] Clean-up around get_x_ish() Junio C Hamano
2020-09-25 5:59 ` [PATCH 1/4] t8013: minimum preparatory clean-up Junio C Hamano
2020-09-25 5:59 ` [PATCH 2/4] blame: validate and peel the object names on the ignore list Junio C Hamano
2020-09-26 16:23 ` René Scharfe
2020-09-26 17:06 ` Junio C Hamano
2020-09-26 23:58 ` Junio C Hamano
2020-09-28 13:26 ` Barret Rhoden
2020-10-11 16:03 ` René Scharfe
2020-10-12 16:54 ` Junio C Hamano
2020-10-12 20:39 ` Barret Rhoden [this message]
2020-10-13 20:12 ` René Scharfe
2020-09-25 5:59 ` [PATCH 3/4] t1506: rev-parse A..B and A...B Junio C Hamano
2020-09-25 5:59 ` [PATCH 4/4] sequencer: stop abbreviating stopped-sha file Junio C Hamano
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