From: Jeff King <peff@peff.net>
To: "SZEDER Gábor" <szeder.dev@gmail.com>
Cc: git@vger.kernel.org, "Junio C Hamano" <gitster@pobox.com>,
"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Subject: Re: [PATCH 2/5] progress: return early when in the background
Date: Tue, 26 Mar 2019 01:38:39 -0400 [thread overview]
Message-ID: <20190326053839.GC1933@sigill.intra.peff.net> (raw)
In-Reply-To: <20190325103844.26749-3-szeder.dev@gmail.com>
On Mon, Mar 25, 2019 at 11:38:41AM +0100, SZEDER Gábor wrote:
> diff --git a/progress.c b/progress.c
> index 02a20e7d58..b57c0dae16 100644
> --- a/progress.c
> +++ b/progress.c
> @@ -86,28 +86,30 @@ static void display(struct progress *progress, uint64_t n, const char *done)
> return;
>
> progress->last_value = n;
> +
> + if (!is_foreground_fd(fileno(stderr)) && !done) {
> + progress_update = 0;
> + return;
> + }
> +
Moving it here causes a measurable slowdown for:
git rev-list --progress=foo --objects --all
This function gets called for every single increment of the progress
counter. Whereas in its old location:
> tp = (progress->throughput) ? progress->throughput->display.buf : "";
> eol = done ? done : " \r";
> if (progress->total) {
> unsigned percent = n * 100 / progress->total;
> if (percent != progress->last_percent || progress_update) {
> progress->last_percent = percent;
> - if (is_foreground_fd(fileno(stderr)) || done) {
> - fprintf(stderr, "%s: %3u%% (%"PRIuMAX"/%"PRIuMAX")%s%s",
> - progress->title, percent,
> - (uintmax_t)n, (uintmax_t)progress->total,
> - tp, eol);
> - fflush(stderr);
> - }
It was only triggered when we accumulated enough increments to print. So
we save a few instructions in the backgrounded case, but it costs us a
lot of extra syscalls in every other case.
According to "strace -c", the number of ioctls for that rev-list on
git.git went from 6 to 373,461. But more importantly, my best-of-five
timings went from 3.340s from 3.407s. That's only 2%, but it would be
nice not to pay it if we don't need to.
-Peff
next prev parent reply other threads:[~2019-03-26 5:38 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-25 10:38 [PATCH 0/5] Progress display fixes SZEDER Gábor
2019-03-25 10:38 ` [PATCH 1/5] progress: make display_progress() return void SZEDER Gábor
2019-03-25 10:38 ` [PATCH 2/5] progress: return early when in the background SZEDER Gábor
2019-03-25 11:08 ` Ævar Arnfjörð Bjarmason
2019-03-25 11:39 ` SZEDER Gábor
2019-03-26 6:28 ` Luke Mewburn
2019-03-26 5:38 ` Jeff King [this message]
2019-03-25 10:38 ` [PATCH 3/5] progress: assemble percentage and counters in a strbuf before printing SZEDER Gábor
2019-03-26 5:45 ` Jeff King
2019-03-27 10:24 ` SZEDER Gábor
2019-03-28 2:12 ` Jeff King
2019-03-25 10:38 ` [PATCH 4/5] progress: clear previous progress update dynamically SZEDER Gábor
2019-03-25 10:38 ` [PATCH 5/5] progress: break too long progress bar lines SZEDER Gábor
2019-03-25 11:02 ` Duy Nguyen
2019-03-25 11:12 ` SZEDER Gábor
2019-03-26 5:52 ` [PATCH 0/5] Progress display fixes Jeff King
2019-04-01 11:52 ` [PATCH v2 0/4] " SZEDER Gábor
2019-04-01 11:52 ` [PATCH v2 1/4] progress: make display_progress() return void SZEDER Gábor
2019-04-02 5:42 ` Eric Sunshine
2019-04-01 11:52 ` [PATCH v2 2/4] progress: assemble percentage and counters in a strbuf before printing SZEDER Gábor
2019-04-02 5:45 ` Eric Sunshine
2019-04-02 5:50 ` Eric Sunshine
2019-04-01 11:52 ` [PATCH v2 3/4] progress: clear previous progress update dynamically SZEDER Gábor
2019-04-01 13:30 ` Jeff King
2019-04-01 14:15 ` SZEDER Gábor
2019-04-02 14:27 ` Jeff King
2019-04-01 11:52 ` [PATCH v2 4/4] progress: break too long progress bar lines SZEDER Gábor
2019-04-05 0:45 ` [PATCH v3 0/4] Progress display fixes SZEDER Gábor
2019-04-05 0:45 ` [PATCH v3 1/4] progress: make display_progress() return void SZEDER Gábor
2019-04-05 0:45 ` [PATCH v3 2/4] progress: assemble percentage and counters in a strbuf before printing SZEDER Gábor
2019-04-05 0:45 ` [PATCH v3 3/4] progress: clear previous progress update dynamically SZEDER Gábor
2019-04-05 0:45 ` [PATCH v3 4/4] progress: break too long progress bar lines SZEDER Gábor
2019-04-05 22:21 ` [PATCH v3 0/4] Progress display fixes Jeff King
2019-04-12 19:45 ` [PATCH v4 " SZEDER Gábor
2019-04-12 19:45 ` [PATCH v4 1/4] progress: make display_progress() return void SZEDER Gábor
2019-04-12 19:45 ` [PATCH v4 2/4] progress: assemble percentage and counters in a strbuf before printing SZEDER Gábor
2019-04-12 19:45 ` [PATCH v4 3/4] progress: clear previous progress update dynamically SZEDER Gábor
2019-04-12 19:45 ` [PATCH v4 4/4] progress: break too long progress bar lines SZEDER Gábor
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