From: Peizhao Ou <peizhaoo@uci.edu>
Date: Wed, 4 Mar 2015 01:31:58 +0000 (-0800)
Subject: spsc example
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=b9a23d48995f9667fc94a85d1309e02811aa153f;p=model-checker-benchmarks.git

spsc example
---

diff --git a/spsc-example/Makefile b/spsc-example/Makefile
new file mode 100644
index 0000000..defccdd
--- /dev/null
+++ b/spsc-example/Makefile
@@ -0,0 +1,11 @@
+include ../benchmarks.mk
+
+TESTNAME = spsc-queue
+
+all: $(TESTNAME)
+
+$(TESTNAME): $(TESTNAME).cc queue.h
+	$(CXX) -o $@ $< $(CXXFLAGS) $(LDFLAGS)
+
+clean:
+	rm -f $(TESTNAME) *.o
diff --git a/spsc-example/note.txt b/spsc-example/note.txt
new file mode 100644
index 0000000..c12ab95
--- /dev/null
+++ b/spsc-example/note.txt
@@ -0,0 +1,2 @@
+This is the example used in the scfence example section in the paper.
+We need to deal with the problem of data races.
diff --git a/spsc-example/queue.h b/spsc-example/queue.h
new file mode 100644
index 0000000..76430e7
--- /dev/null
+++ b/spsc-example/queue.h
@@ -0,0 +1,39 @@
+#include <unrelacy.h>
+#include <atomic>
+
+using namespace std;
+
+struct node {
+	node(int d): data(d) {
+		next.store(0, memory_order_relaxed);
+	}
+	atomic<node*> next;
+	int data;
+};
+
+class spsc_queue
+{
+	atomic<node*> head, tail;
+	public:
+	spsc_queue() {
+		head = tail = new node(0);
+	}
+
+	void enqueue(int val) {
+		node* n = new node(val);
+		node *h = head.load(memory_order_relaxed); 
+		h->next.store(n, memory_order_release);
+		head.store(n, memory_order_relaxed);
+	}
+
+	bool dequeue(int *v) {
+		node* t = tail.load(memory_order_relaxed);
+		node* n = t->next.load(memory_order_acquire);
+		if (0 == n)
+			return false;
+		*v = n->data;
+		tail.store(n, memory_order_relaxed);
+		delete (t);
+		return true;
+	}
+};
diff --git a/spsc-example/spsc-queue.cc b/spsc-example/spsc-queue.cc
new file mode 100644
index 0000000..cfb34ec
--- /dev/null
+++ b/spsc-example/spsc-queue.cc
@@ -0,0 +1,37 @@
+#include <threads.h>
+
+#include "queue.h"
+
+spsc_queue *q;
+atomic_int arr[2];
+
+void thread(unsigned thread_index)
+{
+	if (0 == thread_index)
+	{
+		arr[1].store(memory_order_relaxed);
+		q->enqueue(1);
+	}
+	else
+	{
+		int val = 0;
+		bool succ = q->dequeue(&val);
+		arr[val].load(memory_order_relaxed);
+	}
+}
+
+int user_main(int argc, char **argv)
+{
+	thrd_t A, B;
+
+	q = new spsc_queue();
+
+	thrd_create(&A, (thrd_start_t)&thread, (void *)0);
+	thrd_create(&B, (thrd_start_t)&thread, (void *)1);
+	thrd_join(A);
+	thrd_join(B);
+
+	delete q;
+
+	return 0;
+}