X-Git-Url: https://git.lttng.org/?p=urcu.git;a=blobdiff_plain;f=doc%2Fexamples%2Furcu-flavors%2Fqsbr.c;h=1dbd54635cbe06a4ca71bb9a60fdb87bcb8c9dec;hp=6f5b9b51d46b796adcaf26792dcfcfd5eb1b1c4f;hb=d7818a6fd0c57b576f3bacc67ddd62bc8a78fb05;hpb=9b4bf32b5757c99226eb78bea03f911536f2e9fc

diff --git a/doc/examples/urcu-flavors/qsbr.c b/doc/examples/urcu-flavors/qsbr.c
index 6f5b9b5..1dbd546 100644
--- a/doc/examples/urcu-flavors/qsbr.c
+++ b/doc/examples/urcu-flavors/qsbr.c
@@ -126,6 +126,16 @@ int main(int argc, char **argv)
 
 	rcu_thread_online();
 
+	/*
+	 * We can also wait for a quiescent state by calling
+	 * synchronize_rcu() rather than using call_rcu(). It is usually
+	 * a slower approach than call_rcu(), because the latter can
+	 * batch work. Moreover, call_rcu() can be called from a RCU
+	 * read-side critical section, but synchronize_rcu() ensures the
+	 * caller thread is offline, thus acting as a quiescent state.
+	 */
+	synchronize_rcu();
+
 	/*
 	 * Waiting for previously called call_rcu handlers to complete
 	 * before program exits, or in library destructors, is a good