From: Peizhao Ou <peizhaoo@uci.edu>
Date: Thu, 19 Nov 2015 23:36:16 +0000 (-0800)
Subject: edits
X-Git-Url: http://plrg.eecs.uci.edu/git/?p=cdsspec-compiler.git;a=commitdiff_plain;h=d1aff50233aef12d3f8376bb4646de39f4112560;hp=7537757f9cbddcfa61076053bea0bddad28e37ad

edits
---

diff --git a/benchmark/mpmc-queue/mpmc-queue.h b/benchmark/mpmc-queue/mpmc-queue.h
index ff6a168..046a248 100644
--- a/benchmark/mpmc-queue/mpmc-queue.h
+++ b/benchmark/mpmc-queue/mpmc-queue.h
@@ -134,7 +134,7 @@ public:
 		// (*1)
 		rl::backoff bo;
 		while (true) {
-			/**** Inadmissibility ****/
+			/**** Inadmissibility (testcase2.c) ****/
 			int written = m_written.load(mo_acquire);
 			if ((written & MASK) != wr) {
 				thrd_yield();
@@ -173,7 +173,7 @@ public:
 		@End
 	*/
 	void read_consume(t_element *bin) {
-		/**** Inadmissibility ****/
+		/**** Inadmissibility (testcase1.c) ****/
 		m_read.fetch_add(1,mo_release);
 		/**
 			@Begin
@@ -214,6 +214,14 @@ public:
 				return NULL;
 			}
 			
+			// FIXME: Theoretically we have a bug here, it is not so likely to
+			// happen!!! The following acq_rel can not guarantee that the load
+			// acquire on m_read to read the most recent value. However, it can
+			// decrease the chance of the load acquire of m_read to read a too
+			// old value. Same as the case in read_fetch(). Maybe making things
+			// SC can fix it. We can run testcase3.c to expose this bug (set the
+			// array size  = 1, the MASK = 1).
+			
 			/**** Inadmissibility (testcase3.cc, MASK = 1, size = 1) ****/
 			bool succ = m_rdwr.compare_exchange_weak(rdwr,(rd<<16) |
 				((wr+1)&MASK),mo_acq_rel);
@@ -241,7 +249,7 @@ public:
 		// (*1)
 		rl::backoff bo;
 		while (true) {
-			/**** Inadmissibility ****/
+			/**** Inadmissibility (testcase1.c) ****/
 			int read = m_read.load(mo_acquire);
 			if ((read & MASK) != rd)
 				thrd_yield();
@@ -273,19 +281,19 @@ public:
 	/**
 		@Begin
 		@Interface: Publish 
-		@Commit_point_set: Publish_W_RMW
+		@Commit_point_set: PublishFetchAdd
 		@ID: (call_id_t) bin 
 		//@Action: model_print("Publish: %d\n", bin);
 		@End
 	*/
 	void write_publish(t_element *bin)
 	{
-		/**** Inadmissibility ****/
+		/**** Inadmissibility (testcase2.c) ****/
 		int tmp = m_written.fetch_add(1,mo_release);
 		/**
 			@Begin
 			@Commit_point_define_check: true
-			@Label: Publish_W_RMW
+			@Label: PublishFetchAdd
 			@End
 		*/
 		printf("publish: m_written=%d\n", tmp + 1);
diff --git a/benchmark/mpmc-queue/testcase1.cc b/benchmark/mpmc-queue/testcase1.cc
index 594564f..6a5e21c 100644
--- a/benchmark/mpmc-queue/testcase1.cc
+++ b/benchmark/mpmc-queue/testcase1.cc
@@ -8,7 +8,7 @@
 
 #include "mpmc-queue.h"
 
-void threadA(struct mpmc_boundq_1_alt<int32_t, 2> *queue)
+void threadA(struct mpmc_boundq_1_alt<int32_t, 1> *queue)
 {
 	int32_t *bin;
 	bin = queue->write_prepare();
@@ -21,7 +21,7 @@ void threadA(struct mpmc_boundq_1_alt<int32_t, 2> *queue)
 	}
 }
 
-void threadB(struct mpmc_boundq_1_alt<int32_t, 2> *queue)
+void threadB(struct mpmc_boundq_1_alt<int32_t, 1> *queue)
 {
 	int32_t *bin;
 	bin = queue->read_fetch();
@@ -35,7 +35,7 @@ void threadB(struct mpmc_boundq_1_alt<int32_t, 2> *queue)
 
 int user_main(int argc, char **argv)
 {
-	struct mpmc_boundq_1_alt<int32_t, 2> queue;
+	struct mpmc_boundq_1_alt<int32_t, 1> queue(0xFFFF);
 	thrd_t A, B;
 
 	printf("Adding initial element\n");
@@ -45,11 +45,12 @@ int user_main(int argc, char **argv)
 	printf("init_write_bin %d, val %d\n", bin, 17);
 	queue.write_publish(bin);
 
+/*
 	bin = queue.write_prepare();
 	*bin = 27;
 	printf("init_write_bin %d, val %d\n", bin, 27);
 	queue.write_publish(bin);
-
+*/
 
 	printf("Start threads\n");