svn commit: r216505 - head/sys/cddl/dev/cyclic/i386

Andriy Gapon avg at
Fri Dec 17 18:22:50 UTC 2010

Author: avg
Date: Fri Dec 17 18:22:50 2010
New Revision: 216505

  cyclic xcall: use smp_no_rendevous_barrier as setup function parameter
  In this case we call target function only on a single CPU and do not
  need any synchronization at the setup stage.
  It's a bit non-obvious but setup function of NULL means that
  smp_rendezvous_cpus waits for all CPUs to arrive at the rendezvous
  point, but without doing any actual setup.  While using
  smp_no_rendevous_barrier means that each CPU proceeds on its own
  schedule without any synchronization whatsoever.
  MFC after:	3 weeks


Modified: head/sys/cddl/dev/cyclic/i386/cyclic_machdep.c
--- head/sys/cddl/dev/cyclic/i386/cyclic_machdep.c	Fri Dec 17 16:29:06 2010	(r216504)
+++ head/sys/cddl/dev/cyclic/i386/cyclic_machdep.c	Fri Dec 17 18:22:50 2010	(r216505)
@@ -122,6 +122,6 @@ static void reprogram(cyb_arg_t arg, hrt
 static void xcall(cyb_arg_t arg, cpu_t *c, cyc_func_t func, void *param)
-	smp_rendezvous_cpus((cpumask_t) (1 << c->cpuid), NULL,
-	    func, smp_no_rendevous_barrier, param);
+	smp_rendezvous_cpus((cpumask_t) (1 << c->cpuid),
+	    smp_no_rendevous_barrier, func, smp_no_rendevous_barrier, param);

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