From: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Date: Mon, 9 Feb 2009 00:21:34 +0000 (-0500)
Subject: Add randomness to yield debug test
X-Git-Tag: v0.1~315
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=9d335088c7c7eb6219e32ec9426d336f3a211a77;p=userspace-rcu.git

Add randomness to yield debug test

Add randomness to allow 1/2 odds that the yield will be done.
This lets some paths go quickly and others not.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
---

diff --git a/urcu.c b/urcu.c
index 4362217..83d2fe4 100644
--- a/urcu.c
+++ b/urcu.c
@@ -33,7 +33,8 @@ struct reader_data {
 };
 
 #ifdef DEBUG_YIELD
-int yield_active;
+unsigned int yield_active;
+unsigned int __thread rand_yield;
 #endif
 
 static struct reader_data *reader_data;
diff --git a/urcu.h b/urcu.h
index 2aa3597..c77b26f 100644
--- a/urcu.h
+++ b/urcu.h
@@ -72,18 +72,26 @@ static inline void atomic_inc(int *v)
 #define YIELD_READ 	(1 << 0)
 #define YIELD_WRITE	(1 << 1)
 
-extern int yield_active;
+extern unsigned int yield_active;
+extern unsigned int __thread rand_yield;
 
 static inline void debug_yield_read(void)
 {
 	if (yield_active & YIELD_READ)
-		sched_yield();
+		if (rand_r(&rand_yield) & 0x1)
+			sched_yield();
 }
 
 static inline void debug_yield_write(void)
 {
 	if (yield_active & YIELD_WRITE)
-		sched_yield();
+		if (rand_r(&rand_yield) & 0x1)
+			sched_yield();
+}
+
+static inline void debug_yield_init(void)
+{
+	rand_yield = time(NULL) ^ pthread_self();
 }
 #else
 static inline void debug_yield_read(void)
@@ -92,6 +100,11 @@ static inline void debug_yield_read(void)
 
 static inline void debug_yield_write(void)
 {
+}
+
+static inline void debug_yield_init(void)
+{
+
 }
 #endif