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| author | Jeff King <peff@peff.net> | 2015-04-16 05:01:38 -0400 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2015-04-16 08:15:05 -0700 |
| commit | 0cc30e0e842a25846e76e09f62a1d425a25ee556 (patch) | |
| tree | aa967acf53f4e40271e0b36ab2d188d16eb6973e /config.mak.uname | |
| parent | f80c153bea4e0ea86f5b6d32e77df0b69501ee18 (diff) | |
| download | git-0cc30e0e842a25846e76e09f62a1d425a25ee556.tar.gz | |
strbuf_getwholeline: use getdelim if it is available
We spend a lot of time in strbuf_getwholeline in a tight
loop reading characters from a stdio handle into a buffer.
The libc getdelim() function can do this for us with less
overhead. It's in POSIX.1-2008, and was a GNU extension
before that. Therefore we can't rely on it, but can fall
back to the existing getc loop when it is not available.
The HAVE_GETDELIM knob is turned on automatically for Linux,
where we have glibc. We don't need to set any new
feature-test macros, because we already define _GNU_SOURCE.
Other systems that implement getdelim may need to other
macros (probably _POSIX_C_SOURCE >= 200809L), but we can
address that along with setting the Makefile knob after
testing the feature on those systems.
Running "git rev-parse refs/heads/does-not-exist" on a repo
with an extremely large (1.6GB) packed-refs file went from
(best-of-5):
real 0m8.601s
user 0m8.084s
sys 0m0.524s
to:
real 0m6.768s
user 0m6.340s
sys 0m0.432s
for a wall-clock speedup of 21%.
Based on a patch from Rasmus Villemoes <rv@rasmusvillemoes.dk>.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'config.mak.uname')
| -rw-r--r-- | config.mak.uname | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/config.mak.uname b/config.mak.uname index f4e77cb9e5..d26665fa54 100644 --- a/config.mak.uname +++ b/config.mak.uname @@ -36,6 +36,7 @@ ifeq ($(uname_S),Linux) HAVE_DEV_TTY = YesPlease HAVE_CLOCK_GETTIME = YesPlease HAVE_CLOCK_MONOTONIC = YesPlease + HAVE_GETDELIM = YesPlease endif ifeq ($(uname_S),GNU/kFreeBSD) HAVE_ALLOCA_H = YesPlease |