From: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
To: linux-hotplug@vger.kernel.org
Subject: [PATCH] util: Optimize path_encode
Date: Tue, 21 Oct 2008 10:12:57 +0000 [thread overview]
Message-ID: <48FDAB29.9090401@tuffmail.co.uk> (raw)
strncpy() shows up in profiling.
Since we already know the length, use memcpy() instead.
Measured 2% _user_ cpu time reduction on EeePC coldplug
Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
diff --git a/udev/lib/libudev-util.c b/udev/lib/libudev-util.c
index 0ff121d..6586d1c 100644
--- a/udev/lib/libudev-util.c
+++ b/udev/lib/libudev-util.c
@@ -114,7 +114,6 @@ size_t util_path_encode(char *s, size_t len)
char t[(len * 3)+1];
size_t i, j;
- t[0] = '\0';
for (i = 0, j = 0; s[i] != '\0'; i++) {
if (s[i] = '/') {
memcpy(&t[j], "\\x2f", 4);
@@ -127,8 +126,11 @@ size_t util_path_encode(char *s, size_t len)
j++;
}
}
- t[j] = '\0';
- strncpy(s, t, len);
+ if (len = 0)
+ return j;
+ i = (j < len - 1) ? j : len - 1;
+ memcpy(s, t, i);
+ s[i] = '\0';
return j;
}
next reply other threads:[~2008-10-21 10:12 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-21 10:12 Alan Jenkins [this message]
2008-10-21 11:12 ` [PATCH] util: Optimize path_encode Kay Sievers
2008-10-21 21:41 ` Alan Jenkins
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