From: "René Scharfe" <l.s.r@web.de>
To: Git Mailing List <git@vger.kernel.org>
Cc: "SZEDER Gábor" <szeder.dev@gmail.com>,
"Martin Ågren" <martin.agren@gmail.com>,
"Junio C Hamano" <gitster@pobox.com>
Subject: [PATCH 08/10] name-rev: pre-size buffer in get_parent_name()
Date: Tue, 4 Feb 2020 22:24:24 +0100 [thread overview]
Message-ID: <c7f22d8d-10f8-0c97-672e-0a50182901e0@web.de> (raw)
In-Reply-To: <084909f8-fefa-1fe0-b2ce-74eff47c4972@web.de>
We can calculate the size of new name easily and precisely. Open-code
the xstrfmt() calls and grow the buffers as needed before filling them.
This provides a surprisingly large benefit when working with the
Chromium repository; here are the numbers measured using hyperfine
before:
Benchmark #1: ./git -C ../chromium/src name-rev --all
Time (mean ± σ): 5.822 s ± 0.013 s [User: 5.304 s, System: 0.516 s]
Range (min … max): 5.803 s … 5.837 s 10 runs
... and with this patch:
Benchmark #1: ./git -C ../chromium/src name-rev --all
Time (mean ± σ): 1.527 s ± 0.003 s [User: 1.015 s, System: 0.511 s]
Range (min … max): 1.524 s … 1.535 s 10 runs
Signed-off-by: René Scharfe <l.s.r@web.de>
---
builtin/name-rev.c | 20 ++++++++++++++------
1 file changed, 14 insertions(+), 6 deletions(-)
diff --git a/builtin/name-rev.c b/builtin/name-rev.c
index 6701fb1569..793356edd1 100644
--- a/builtin/name-rev.c
+++ b/builtin/name-rev.c
@@ -103,15 +103,23 @@ static struct rev_name *create_or_update_name(struct commit *commit,
static char *get_parent_name(const struct rev_name *name, int parent_number)
{
+ struct strbuf sb = STRBUF_INIT;
size_t len;
strip_suffix(name->tip_name, "^0", &len);
- if (name->generation > 0)
- return xstrfmt("%.*s~%d^%d", (int)len, name->tip_name,
- name->generation, parent_number);
- else
- return xstrfmt("%.*s^%d", (int)len, name->tip_name,
- parent_number);
+ if (name->generation > 0) {
+ strbuf_grow(&sb, len +
+ 1 + decimal_width(name->generation) +
+ 1 + decimal_width(parent_number));
+ strbuf_addf(&sb, "%.*s~%d^%d", (int)len, name->tip_name,
+ name->generation, parent_number);
+ } else {
+ strbuf_grow(&sb, len +
+ 1 + decimal_width(parent_number));
+ strbuf_addf(&sb, "%.*s^%d", (int)len, name->tip_name,
+ parent_number);
+ }
+ return strbuf_detach(&sb, NULL);
}
static void name_rev(struct commit *start_commit,
--
2.25.0
next prev parent reply other threads:[~2020-02-04 21:24 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-04 21:12 [PATCH 00/10] name-rev: improve memory usage René Scharfe
2020-02-04 21:14 ` [PATCH 01/10] name-rev: rewrite create_or_update_name() René Scharfe
2020-02-05 2:00 ` Derrick Stolee
2020-02-05 2:35 ` Taylor Blau
2020-02-05 16:45 ` Andrei Rybak
2020-02-05 16:47 ` René Scharfe
2020-02-04 21:15 ` [PATCH 02/10] name-rev: remove unused typedef René Scharfe
2020-02-04 21:16 ` [PATCH 03/10] name-rev: respect const qualifier René Scharfe
2020-02-04 21:17 ` [PATCH 04/10] name-rev: don't leak path copy in name_ref() René Scharfe
2020-02-05 14:35 ` Derrick Stolee
2020-02-04 21:20 ` [PATCH 05/10] name-rev: don't _peek() in create_or_update_name() René Scharfe
2020-02-04 21:22 ` [PATCH 06/10] name-rev: put struct rev_name into commit slab René Scharfe
2020-02-04 21:23 ` [PATCH 07/10] name-rev: factor out get_parent_name() René Scharfe
2020-02-04 21:24 ` René Scharfe [this message]
2020-02-05 3:19 ` [PATCH 08/10] name-rev: pre-size buffer in get_parent_name() Derrick Stolee
2020-02-05 15:16 ` René Scharfe
2020-02-04 21:25 ` [PATCH 09/10] name-rev: generate name strings only if they are better René Scharfe
2020-02-05 15:11 ` Derrick Stolee
2020-02-05 15:50 ` René Scharfe
2020-02-04 21:26 ` [PATCH 10/10] name-rev: release unused name strings René Scharfe
2020-02-05 15:19 ` Derrick Stolee
2020-02-05 3:28 ` [PATCH 00/10] name-rev: improve memory usage Derrick Stolee
2020-02-05 15:20 ` Derrick Stolee
2020-02-05 17:19 ` [PATCH 01/10 RESEND AUTHOR FIXED] name-rev: rewrite create_or_update_name() René Scharfe
2020-02-05 17:50 ` [PATCH 11/10] name-rev: sort tip names before applying René Scharfe
2020-02-05 18:23 ` Junio C Hamano
2020-02-05 18:55 ` René Scharfe
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