From mboxrd@z Thu Jan  1 00:00:00 1970
From: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Date: Sat, 25 Oct 2008 16:01:21 +0000
Subject: [PATCH] udevd: Use a tighter loop in compare_devpath()
Message-Id: <490342D1.9090906@tuffmail.co.uk>
List-Id: <linux-hotplug.vger.kernel.org>
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To: linux-hotplug@vger.kernel.org

udevd: Use a tighter loop for compare_devpath()

This crops up in my threaded udevd profiles from time to time.
It's not consistent - probably due to variations in the number
of concurrent events - but it can hit 4% user time and higher.

The change halves the user time spent in compare_devpath().

Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>

diff --git a/udev/udevd.c b/udev/udevd.c
index 4306597..381d560 100644
@@ -303,26 +285,24 @@ static int mem_size_mb(void)
 
 static int compare_devpath(const char *running, const char *waiting)
 {
-	int i;
+	int i = 0;
 
-	for (i = 0; i < UTIL_PATH_SIZE; i++) {
-		/* identical device event found */
-		if (running[i] = '\0' && waiting[i] = '\0')
-			return 1;
+	while (running[i] = waiting[i] && running[i] != '\0')
+		i++;
 
-		/* parent device event found */
-		if (running[i] = '\0' && waiting[i] = '/')
-			return 2;
+	/* identical device event found */
+	if (running[i] = '\0' && waiting[i] = '\0')
+		return 1;
 
-		/* child device event found */
-		if (running[i] = '/' && waiting[i] = '\0')
-			return 3;
+	/* parent device event found */
+	if (running[i] = '\0' && waiting[i] = '/')
+		return 2;
 
-		/* no matching event */
-		if (running[i] != waiting[i])
-			break;
-	}
+	/* child device event found */
+	if (running[i] = '/' && waiting[i] = '\0')
+		return 3;
 
+	/* no matching event */
 	return 0;
 }