From: "Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>
To: git@vger.kernel.org, Junio C Hamano <gitster@pobox.com>,
dpmcgee@gmail.com
Cc: "Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>
Subject: [PATCH] tree_entry_interesting: inline strncmp()
Date: Mon, 4 Apr 2011 21:46:26 +0700 [thread overview]
Message-ID: <1301928386-25038-1-git-send-email-pclouds@gmail.com> (raw)
In-Reply-To: <1301535481-1085-3-git-send-email-dpmcgee@gmail.com>
strncmp() is the function that takes most of the time inside
tree_entry_interesting(). Inline it so we can shave some seconds out
of function call time.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
Turns out simplicity is the best. My straight copy of strncmp from
glibc performed worse.
With this I get a slightly better performance than Dan's 3/5:
81.07-82.27 secs versus 82.02-82.92 (no other patches are applied).
But I'm happy even if it gives the same or slightly worse
performance because this applies to more cases than flat top tree
case.
Dan, match_dir_prefix() can also use some reordering to avoid
strncmp(). But I suppose it won't give much gain on packages.git
tree-walk.c | 28 ++++++++++++++++++++++++----
1 files changed, 24 insertions(+), 4 deletions(-)
diff --git a/tree-walk.c b/tree-walk.c
index 322becc..80bfc3a 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -457,6 +457,26 @@ int get_tree_entry(const unsigned char *tree_sha1, const char *name, unsigned ch
return retval;
}
+/* Static version of strncmp to reduce function call cost */
+static inline int strncmp_1(const char *s1, const char *s2, size_t n)
+{
+ unsigned char c1 = '\0';
+ unsigned char c2 = '\0';
+
+ if (!n)
+ return 0;
+
+ while (n > 0) {
+ c1 = (unsigned char) *s1++;
+ c2 = (unsigned char) *s2++;
+ if (c1 == '\0' || c1 != c2)
+ return c1 - c2;
+ n--;
+ }
+
+ return c1 - c2;
+}
+
static int match_entry(const struct name_entry *entry, int pathlen,
const char *match, int matchlen,
int *never_interesting)
@@ -473,7 +493,7 @@ static int match_entry(const struct name_entry *entry, int pathlen,
* Does match sort strictly earlier than path
* with their common parts?
*/
- m = strncmp(match, entry->path,
+ m = strncmp_1(match, entry->path,
(matchlen < pathlen) ? matchlen : pathlen);
if (m < 0)
return 0;
@@ -509,7 +529,7 @@ static int match_entry(const struct name_entry *entry, int pathlen,
* we cheated and did not do strncmp(), so we do
* that here.
*/
- m = strncmp(match, entry->path, pathlen);
+ m = strncmp_1(match, entry->path, pathlen);
/*
* If common part matched earlier then it is a hit,
@@ -525,7 +545,7 @@ static int match_entry(const struct name_entry *entry, int pathlen,
static int match_dir_prefix(const char *base, int baselen,
const char *match, int matchlen)
{
- if (strncmp(base, match, matchlen))
+ if (strncmp_1(base, match, matchlen))
return 0;
/*
@@ -592,7 +612,7 @@ int tree_entry_interesting(const struct name_entry *entry,
}
/* Does the base match? */
- if (!strncmp(base_str, match, baselen)) {
+ if (!strncmp_1(base_str, match, baselen)) {
if (match_entry(entry, pathlen,
match + baselen, matchlen - baselen,
&never_interesting))
--
1.7.4.74.g639db
next prev parent reply other threads:[~2011-04-04 14:49 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-31 1:37 [PATCH 1/5] diff_tree_sha1: skip diff_tree if old == new Dan McGee
2011-03-31 1:37 ` [PATCH 2/5] tree-walk: drop unused parameter from match_dir_prefix Dan McGee
2011-08-30 18:55 ` Dan McGee
2011-03-31 1:37 ` [PATCH 3/5] tree-walk: micro-optimization in tree_entry_interesting Dan McGee
2011-04-03 4:01 ` Nguyen Thai Ngoc Duy
2011-04-03 18:55 ` Junio C Hamano
2011-04-05 0:22 ` Dan McGee
[not found] ` <CAEik5nOKrpFycZYVnSu4_5LYWxn0JS_hVXyiQH-80Bu-C4k8VQ@mail.gmail.com>
2011-08-30 19:51 ` Dan McGee
2011-08-30 20:40 ` Junio C Hamano
2011-09-09 2:02 ` [PATCH 1/2] tree-walk: drop unused parameter from match_dir_prefix Dan McGee
2011-09-09 2:02 ` [PATCH 2/2] tree-walk: micro-optimization in tree_entry_interesting Dan McGee
2011-04-04 14:46 ` Nguyễn Thái Ngọc Duy [this message]
2011-03-31 1:38 ` [PATCH 4/5] tree-walk: unroll get_mode since loop boundaries are well-known Dan McGee
2011-04-02 9:28 ` Nguyen Thai Ngoc Duy
2011-04-02 17:28 ` Dan McGee
2011-04-03 4:07 ` Nguyen Thai Ngoc Duy
2011-04-04 10:29 ` Erik Faye-Lund
2011-04-04 12:30 ` Andreas Ericsson
2011-04-04 16:55 ` Junio C Hamano
2011-04-05 5:33 ` Dan McGee
2011-04-05 23:55 ` Antriksh Pany
2011-04-06 20:45 ` Dan McGee
2011-03-31 1:38 ` [PATCH 5/5] tree-walk: match_entry microoptimization Dan McGee
2011-04-02 9:06 ` Nguyen Thai Ngoc Duy
2011-04-02 17:54 ` Dan McGee
2011-03-31 12:58 ` [PATCH 1/5] diff_tree_sha1: skip diff_tree if old == new Nguyen Thai Ngoc Duy
2011-03-31 13:56 ` Dan McGee
2011-04-01 22:28 ` Junio C Hamano
[not found] ` <AANLkTinPSqDPdGi5nA3sH1D2wMSW1SQc+5gRqdLy++y0@mail.gmail.com>
2011-04-02 18:38 ` Fwd: " Dan McGee
2011-05-03 7:34 ` Nguyen Thai Ngoc Duy
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