From: Joel Rosdahl <joel@rosdahl.net>
Date: Tue, 20 Jul 2010 22:13:39 +0000 (+0200)
Subject: Always update a stats file in a subdirectory to reduce lock contention
X-Git-Tag: v3.1~136
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=f4e92259b63e978bf027de2aac9e277ba951f91f;p=thirdparty%2Fccache.git

Always update a stats file in a subdirectory to reduce lock contention
---

diff --git a/stats.c b/stats.c
index 2c854c27e..841e97c5d 100644
--- a/stats.c
+++ b/stats.c
@@ -23,6 +23,7 @@
  */
 
 #include "ccache.h"
+#include "hashutil.h"
 
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -176,13 +177,17 @@ void stats_flush(void)
 	if (!should_flush) return;
 
 	if (!stats_file) {
+		char *stats_dir;
+
 		/*
 		 * A NULL stats_file means that we didn't get past calculate_object_hash(),
-		 * so we update the counter in the cache-wide statistics file
-		 * CCACHE_DIR/stats instead of a subdirectory stats file.
+		 * so we just choose one of stats files in the 16 subdirectories.
 		 */
 		if (!cache_dir) return;
-		stats_file = format("%s/stats", cache_dir);
+		stats_dir = format("%s/%x", cache_dir, hash_from_int(getpid()) % 16);
+		stats_file = format("%s/stats", stats_dir);
+		create_dir(stats_dir);
+		free(stats_dir);
 	}
 
 	fd = safe_open(stats_file);