Hi,
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.
Tim Chen
Signed-off-by: Tim Chen <[email protected]>
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
--- 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
-
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