From: Tim Chen 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 Cc: Ingo Molnar Signed-off-by: Andrew Morton --- lib/Kconfig.debug | 2 +- 1 files changed, 1 insertion(+), 1 deletion(-) diff -puN lib/Kconfig.debug~kconfigdebug-set-debug_mutex-to-off-by-default lib/Kconfig.debug --- devel/lib/Kconfig.debug~kconfigdebug-set-debug_mutex-to-off-by-default 2006-04-07 21:51:09.000000000 -0700 +++ devel-akpm/lib/Kconfig.debug 2006-04-07 21:51:09.000000000 -0700 @@ -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 _