On 26/03/14 09:22, Gonglei (Arei) wrote: > Without patches, ping time can jump from 0.3ms to 2ms-30ms. With > synchronize_srcu > patch, ping time is worse. With synchronize_srcu_expedited patch, ping time > is > overall good, though sometimes ping time jump to 1ms-3ms.
Just to understand whats going on, does something like diff --git a/kernel/rcu/srcu.c b/kernel/rcu/srcu.c index 3318d82..432c2a2 100644 --- a/kernel/rcu/srcu.c +++ b/kernel/rcu/srcu.c @@ -331,7 +331,7 @@ EXPORT_SYMBOL_GPL(__srcu_read_unlock); */ #define SRCU_RETRY_CHECK_DELAY 5 #define SYNCHRONIZE_SRCU_TRYCOUNT 2 -#define SYNCHRONIZE_SRCU_EXP_TRYCOUNT 12 +#define SYNCHRONIZE_SRCU_EXP_TRYCOUNT 50 /* * @@@ Wait until all pre-existing readers complete. Such readers make the problem go away?
