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From: Jeff King <peff@peff.net>
To: git@vger.kernel.org
Subject: [PATCH 1/6] strbuf_getwholeline: use getc macro
Date: Sat, 4 Apr 2015 21:07:35 -0400	[thread overview]
Message-ID: <20150405010734.GA30127@peff.net> (raw)
In-Reply-To: <20150405010611.GA15901@peff.net>

strbuf_getwholeline calls fgetc in a tight loop. Using the
getc form, which can be implemented as a macro, should be
faster (and we do not care about it evaluating our argument
twice, as we just have a plain variable).

On my glibc system, running "git rev-parse
refs/heads/does-not-exist" on a file with an extremely large
(1.6GB) packed-refs file went from (best of 3 runs):

  real    0m19.383s
  user    0m18.876s
  sys     0m0.528s

to:

  real    0m18.900s
  user    0m18.472s
  sys     0m0.448s

for a wall-clock speedup of 2.5%.

Signed-off-by: Jeff King <peff@peff.net>
---
Not that exciting a speedup. But later we will switch to getc_unlocked,
and I wanted to measure how much of that was coming from the macro, and
how much from the locking.

 strbuf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/strbuf.c b/strbuf.c
index 88cafd4..14f337d 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -443,7 +443,7 @@ int strbuf_getwholeline(struct strbuf *sb, FILE *fp, int term)
 		return EOF;
 
 	strbuf_reset(sb);
-	while ((ch = fgetc(fp)) != EOF) {
+	while ((ch = getc(fp)) != EOF) {
 		strbuf_grow(sb, 1);
 		sb->buf[sb->len++] = ch;
 		if (ch == term)
-- 
2.4.0.rc0.363.gf9f328b

  reply	other threads:[~2015-04-05  1:07 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-05  1:06 [PATCH 0/6] address packed-refs speed regressions Jeff King
2015-04-05  1:07 ` Jeff King [this message]
2015-04-05  1:08 ` [PATCH 2/6] git-compat-util: add fallbacks for unlocked stdio Jeff King
2015-04-05  1:11 ` [PATCH 3/6] strbuf_getwholeline: use getc_unlocked Jeff King
2015-04-05  4:56   ` Jeff King
2015-04-05  5:27     ` Jeff King
2015-04-05  5:35       ` Jeff King
2015-04-05 20:49         ` Junio C Hamano
2015-04-05 14:36     ` Duy Nguyen
2015-04-05 18:24       ` Jeff King
2015-04-05 20:09     ` Junio C Hamano
2015-04-07 13:48     ` Rasmus Villemoes
2015-04-07 19:04       ` Jeff King
2015-04-07 22:43         ` Rasmus Villemoes
2015-04-08  0:17           ` Jeff King
2015-04-05  1:11 ` [PATCH 4/6] strbuf: add an optimized 1-character strbuf_grow Jeff King
2015-04-06  2:13   ` Eric Sunshine
2015-04-06  5:05     ` Jeff King
2015-04-05  1:11 ` [PATCH 5/6] t1430: add another refs-escape test Jeff King
2015-04-05  1:15 ` [PATCH 6/6] refname_is_safe: avoid expensive normalize_path_copy call Jeff King
2015-04-05 13:41 ` [PATCH 0/6] address packed-refs speed regressions René Scharfe
2015-04-05 18:52   ` Jeff King
2015-04-05 18:59     ` Jeff King
2015-04-05 23:04       ` René Scharfe
2015-04-05 22:39     ` René Scharfe
2015-04-06  4:49       ` Jeff King
2015-04-16  8:47 ` [PATCH v2 0/9] " Jeff King
2015-04-16  8:48   ` [PATCH 1/9] strbuf_getwholeline: use getc macro Jeff King
2015-04-16  8:48   ` [PATCH 2/9] git-compat-util: add fallbacks for unlocked stdio Jeff King
2015-04-16  8:49   ` [PATCH 3/9] strbuf_getwholeline: use getc_unlocked Jeff King
2015-04-16  8:51   ` [PATCH 4/9] config: use getc_unlocked when reading from file Jeff King
2015-04-16  8:53   ` [PATCH 5/9] strbuf_addch: avoid calling strbuf_grow Jeff King
2015-04-16  8:58   ` [PATCH 6/9] strbuf_getwholeline: " Jeff King
2015-04-16  9:01   ` [PATCH 7/9] strbuf_getwholeline: use getdelim if it is available Jeff King
2015-04-17 10:16     ` Eric Sunshine
2015-04-21 23:09       ` Jeff King
2015-05-08 23:56         ` Eric Sunshine
2015-05-09  1:09           ` Jeff King
2015-06-02 18:22             ` Eric Sunshine
2015-04-22 18:00       ` Johannes Schindelin
2015-04-22 18:06         ` Jeff King
2015-04-16  9:03   ` [PATCH 8/9] read_packed_refs: avoid double-checking sane refs Jeff King
2015-04-16  9:04   ` [PATCH 9/9] t1430: add another refs-escape test Jeff King
2015-04-16  9:25   ` [PATCH v2 0/9] address packed-refs speed regressions Jeff King

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