From fec501dae8bf6c8fdcd4124c94f37c4cbc26ba29 Mon Sep 17 00:00:00 2001 From: Jeff King Date: Thu, 16 Apr 2015 04:53:56 -0400 Subject: strbuf_addch: avoid calling strbuf_grow We mark strbuf_addch as inline, because we expect it may be called from a tight loop. However, the first thing it does is call the non-inline strbuf_grow(), which can handle arbitrary-sized growth. Since we know that we only need a single character, we can use the inline strbuf_avail() to quickly check whether we need to grow at all. Our check is redundant when we do call strbuf_grow(), but that's OK. The common case is that we avoid calling it at all, and we have made that case faster. On a silly pathological case: perl -le ' print "[core]"; print "key$_ = value$_" for (1..1000000) ' >input git config -f input core.key1 this dropped the time to run git-config from: real 0m0.159s user 0m0.152s sys 0m0.004s to: real 0m0.140s user 0m0.136s sys 0m0.004s for a savings of 12%. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano --- strbuf.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'strbuf.h') diff --git a/strbuf.h b/strbuf.h index 1883494ca3..01c5c6371b 100644 --- a/strbuf.h +++ b/strbuf.h @@ -205,7 +205,8 @@ extern int strbuf_cmp(const struct strbuf *, const struct strbuf *); */ static inline void strbuf_addch(struct strbuf *sb, int c) { - strbuf_grow(sb, 1); + if (!strbuf_avail(sb)) + strbuf_grow(sb, 1); sb->buf[sb->len++] = c; sb->buf[sb->len] = '\0'; } -- cgit v1.2.3