medfall

commit 2344de768015b2fa90ae555e45474d7b58cc5539
parent f728e46141cf91b103e25b1557fbc8bc74cf6005
Author: Michael Savage <mikejsavage@gmail.com>
Date:   Thu Sep  1 13:22:53 -0700

Allow any SPSC queue size

Diffstat:
nonblocking_fixed_spsc_queue.h
 | 
14
+++++---------
relacy.cc
 | 
2
+-
2 files changed, 6 insertions(+), 10 deletions(-)
diff --git a/nonblocking_fixed_spsc_queue.h b/nonblocking_fixed_spsc_queue.h
@@ -8,10 +8,6 @@
 
 template< typename T, u64 N >
 class NonblockingFixedSPSCQueue : public NonblockingQueue< T > {
-	// N really only needs to divide U64_MAX but requiring a power of 2 is
-	// not a problem
-	static_assert( is_power_of_2( N ) );
-
 public:
 	NonblockingFixedSPSCQueue() {
 		clear();
@@ -19,12 +15,12 @@ public:
 
 	// returns true if x was enqueued, false if the queue was full
 	bool enqueue( const T & x ) {
-		u64 w = VAR( writer_pos ) % N;
+		size_t w = VAR( writer_pos );
 		if( load_acquire( &nodes[ w ].last_op ) == WRITE ) return false;
 
 		nodes[ w ].data = x;
 		store_release( &nodes[ w ].last_op, WRITE );
-		VAR( writer_pos )++;
+		VAR( writer_pos ) = ( w + 1 ) % N;
 
 		return true;
 	}
@@ -35,7 +31,7 @@ public:
 	T * dequeue_acquire() {
 		// assert( !reader_acquired );
 
-		u64 r = VAR( reader_pos ) % N;
+		size_t r = VAR( reader_pos );
 		if( load_acquire( &nodes[ r ].last_op ) == READ ) return NULL;
 
 		VAR( reader_acquired ) = true;
@@ -46,9 +42,9 @@ public:
 		// assert( reader_acquired );
 		VAR( reader_acquired ) = false;
 
-		u64 r = VAR( reader_pos ) % N;
+		size_t r = VAR( reader_pos );
 		store_release( &nodes[ r ].last_op, READ );
-		VAR( reader_pos )++;
+		VAR( reader_pos ) = ( r + 1 ) % N;
 	}
 
 	void clear() {
diff --git a/relacy.cc b/relacy.cc
@@ -3,7 +3,7 @@
 #include "intrinsics.h"
 #include "nonblocking_fixed_spsc_queue.h"
 
-#define QUEUE_SIZE 64
+#define QUEUE_SIZE 67
 #define ITERS 256
 
 struct NonblockingFixedSPSCQueueTest : rl::test_suite< NonblockingFixedSPSCQueueTest, 2 > {