Le Wed, Jul 09, 2025 at 04:11:16PM +0530, [email protected] a écrit : > From: "Uladzislau Rezki (Sony)" <[email protected]> > > Automatically enable the rcu_normal_wake_from_gp parameter on > systems with a small number of CPUs. The activation threshold > is set to 16 CPUs. > > This helps to reduce a latency of normal synchronize_rcu() API > by waking up GP-waiters earlier and decoupling synchronize_rcu() > callers from regular callback handling. > > A benchmark running 64 parallel jobs(system with 64 CPUs) invoking > synchronize_rcu() demonstrates a notable latency reduction with the > setting enabled. > > Latency distribution (microseconds): > > <default> > 0 - 9999 : 1 > 10000 - 19999 : 4 > 20000 - 29999 : 399 > 30000 - 39999 : 3197 > 40000 - 49999 : 10428 > 50000 - 59999 : 17363 > 60000 - 69999 : 15529 > 70000 - 79999 : 9287 > 80000 - 89999 : 4249 > 90000 - 99999 : 1915 > 100000 - 109999 : 922 > 110000 - 119999 : 390 > 120000 - 129999 : 187 > ... > <default> > > <rcu_normal_wake_from_gp> > 0 - 9999 : 1 > 10000 - 19999 : 234 > 20000 - 29999 : 6678 > 30000 - 39999 : 33463 > 40000 - 49999 : 20669 > 50000 - 59999 : 2766 > 60000 - 69999 : 183 > ... > <rcu_normal_wake_from_gp> > > Reviewed-by: Joel Fernandes <[email protected]> > Signed-off-by: Uladzislau Rezki (Sony) <[email protected]> > Signed-off-by: Neeraj Upadhyay (AMD) <[email protected]>
Reviewed-by: Frederic Weisbecker <[email protected]> -- Frederic Weisbecker SUSE Labs
