[PATCH] Kconfig.debug: Set DEBUG_MUTEX to off by default

DEBUG_MUTEX flag is on by default in current kernel configuration. During performance testing, we saw mutex debug functions like mutex_debug_check_no_locks_freed (called by kfree()) is expensive as it goes through a global list of memory areas with mutex lock and do the checking. For benchmarks such as Volanomark and Hackbench, we have seen more than 40% drop in performance on some platforms. We suggest to set DEBUG_MUTEX off by default. Or at least do that later when we feel that the mutex changes in the current code have stabilized. Signed-off-by: Tim Chen <[email protected]> Cc: Ingo Molnar <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
kyagi · Apr 19, 2006 · cca57c5 · cca57c5
1 parent ca99c1d
commit cca57c5
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
@@ -101,7 +101,7 @@ config DEBUG_PREEMPT
 
 config DEBUG_MUTEXES
 	bool "Mutex debugging, deadlock detection"
-	default y
+	default n
 	depends on DEBUG_KERNEL
 	help
 	 This allows mutex semantics violations and mutex related deadlocks