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: Nguyán ThÃi Ngác Duy <pclouds@xxxxxxxxx>
---
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
--
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