Adding prefetching.

3 files changed, 51 insertions, 8 deletions

diff --git a/src/Experiment.cpp b/src/Experiment.cpp
index 04fb9ef..e9fbdfa 100644
--- a/src/Experiment.cpp
+++ b/src/Experiment.cpp
@@ -40,7 +40,8 @@ Experiment::Experiment() :
     busy_cycles      (DEFAULT_BUSY_CYCLES),
     seconds          (DEFAULT_SECONDS),
     iterations       (DEFAULT_ITERATIONS),
-    experiments      (DEFAULT_EXPERIMENTS), 
+    experiments      (DEFAULT_EXPERIMENTS),
+    prefetch         (DEFAULT_PREFETCH),
     output_mode      (TABLE),
     access_pattern   (RANDOM),
     stride           (1),
@@ -68,6 +69,7 @@ Experiment::~Experiment()
 				// -i or --iters            iterations
 				// -e or --experiments      experiments
 				// -b or --busy				amount of cycles processor should remain busy
+				// -f or --prefetch			prefetch data
 				// -a or --access           memory access pattern
 				//         random           random access pattern
 				//         forward <stride> exclusive OR and mask
@@ -137,6 +139,8 @@ Experiment::parse_args(int argc, char* argv[])
 	    if (i == argc) { error = 1; break; }
 	    this->busy_cycles = Experiment::parse_number(argv[i]);
 	    if (this->experiments == 0) { error = 1; break; }
+	} else if (strcasecmp(argv[i], "-f") == 0 || strcasecmp(argv[i], "--prefetch") == 0) {
+	    this->prefetch = true;
 	} else if (strcasecmp(argv[i], "-a") == 0 || strcasecmp(argv[i], "--access") == 0) {
 	    i++;
 	    if (i == argc) { error = 1; break; }
@@ -229,6 +233,7 @@ Experiment::parse_args(int argc, char* argv[])
 	printf("    [-n|--numa]        <placement> # numa placement\n");
 	printf("    [-s|--seconds]     <number>    # run each experiment for <number> seconds\n");
 	printf("    [-b|--busy]        <number>    # how much processing cycles each loop should count\n");
+	printf("    [-f|--prefetch]                # prefetch data\n");
 	printf("    [-x|--strict]                  # fail rather than adjust options to sensible values\n");
 	printf("\n");
 	printf("<pattern> is selected from the following:\n");
diff --git a/src/Experiment.h b/src/Experiment.h
index 4c0ae90..38756f0 100644
--- a/src/Experiment.h
+++ b/src/Experiment.h
@@ -44,6 +44,7 @@ public:
     int64 num_threads;		// number of threads in the experiment
     int64 bytes_per_test;	// test working set size (bytes)
     int64 busy_cycles;		// processing cycles
+    bool prefetch;			// use of prefetching
 
     float seconds;		// number of seconds per experiment
     int64 iterations;		// number of iterations per experiment
@@ -91,6 +92,7 @@ public:
     const static int32 DEFAULT_EXPERIMENTS       = 1;
 
     const static int32 DEFAULT_OUTPUT_MODE       = 1;
+    const static bool DEFAULT_PREFETCH           = false;
 
     void alloc_local();
     void alloc_xor();
diff --git a/src/Run.cpp b/src/Run.cpp
index 1ea4db3..049a115 100644
--- a/src/Run.cpp
+++ b/src/Run.cpp
@@ -27,14 +27,16 @@
 
 static double max( double v1, double v2 );
 static double min( double v1, double v2 );
-static void chase_pointers(int64 chains_per_thread, int64 iterations, Chain** root, int64 bytes_per_line, int64 bytes_per_chain, int64 stride, int64 busy_cycles);
-static void follow_streams(int64 chains_per_thread, int64 iterations, Chain** root, int64 bytes_per_line, int64 bytes_per_chain, int64 stride, int64 busy_cycles);
-static void (*run_benchmark)(int64 chains_per_thread, int64 iterations, Chain** root, int64 bytes_per_line, int64 bytes_per_chain, int64 stride, int64 busy_cycles) = chase_pointers;
+static void chase_pointers(int64 chains_per_thread, int64 iterations, Chain** root, int64 bytes_per_line, int64 bytes_per_chain, int64 stride, int64 busy_cycles, bool prefetch);
+static void follow_streams(int64 chains_per_thread, int64 iterations, Chain** root, int64 bytes_per_line, int64 bytes_per_chain, int64 stride, int64 busy_cycles, bool prefetch);
+static void (*run_benchmark)(int64 chains_per_thread, int64 iterations, Chain** root, int64 bytes_per_line, int64 bytes_per_chain, int64 stride, int64 busy_cycles, bool prefetch) = chase_pointers;
 
 Lock   Run::global_mutex;
 int64  Run::_ops_per_chain = 0;
 double Run::_seconds       = 1E9;
 
+#define prefetch(x) __builtin_prefetch(x)
+
 Run::Run()
 : exp(NULL), bp(NULL)
 {
@@ -120,7 +122,7 @@ Run::run()
 	    this->bp->barrier();
 
 				// chase pointers
-	    run_benchmark(this->exp->chains_per_thread, iters, root, this->exp->bytes_per_line, this->exp->bytes_per_chain, this->exp->stride, this->exp->busy_cycles);
+	    run_benchmark(this->exp->chains_per_thread, iters, root, this->exp->bytes_per_line, this->exp->bytes_per_chain, this->exp->stride, this->exp->busy_cycles, this->exp->prefetch);
 
 				// barrier
 	    this->bp->barrier();
@@ -156,7 +158,7 @@ Run::run()
 	this->bp->barrier();
 
 				// chase pointers
-	run_benchmark(this->exp->chains_per_thread, this->exp->iterations, root, this->exp->bytes_per_line, this->exp->bytes_per_chain, this->exp->stride, this->exp->busy_cycles);
+	run_benchmark(this->exp->chains_per_thread, this->exp->iterations, root, this->exp->bytes_per_line, this->exp->bytes_per_chain, this->exp->stride, this->exp->busy_cycles, this->exp->prefetch);
 
 				// barrier
 	this->bp->barrier();
@@ -349,7 +351,8 @@ chase_pointers(
     int64 bytes_per_line,		// ignored
     int64 bytes_per_chain,		// ignored
     int64 stride,			// ignored
-    int64 busy_cycles	// processing cycles
+    int64 busy_cycles,	// processing cycles
+    bool prefetch		// prefetch?
 )
 {
 				// chase pointers
@@ -360,6 +363,8 @@ chase_pointers(
 	    Chain* a = root[0];
 	    while (a != NULL) {
 		a = a->next;
+		if (prefetch)
+			prefetch(a->next);
 		for (int64 j=0; j < busy_cycles; j++)
 			asm("nop");
 	    }
@@ -373,6 +378,8 @@ chase_pointers(
 	    while (a != NULL) {
 		a = a->next;
 		b = b->next;
+		if (prefetch)
+					prefetch(a->next);
 		for (int64 j=0; j < busy_cycles; j++)
 			asm("nop");
 	    }
@@ -389,6 +396,8 @@ chase_pointers(
 		a = a->next;
 		b = b->next;
 		c = c->next;
+		if (prefetch)
+					prefetch(a->next);
 		for (int64 j=0; j < busy_cycles; j++)
 			asm("nop");
 	    }
@@ -408,6 +417,8 @@ chase_pointers(
 		b = b->next;
 		c = c->next;
 		d = d->next;
+		if (prefetch)
+					prefetch(a->next);
 		for (int64 j=0; j < busy_cycles; j++)
 			asm("nop");
 	    }
@@ -430,6 +441,8 @@ chase_pointers(
 		c = c->next;
 		d = d->next;
 		e = e->next;
+		if (prefetch)
+					prefetch(a->next);
 		for (int64 j=0; j < busy_cycles; j++)
 			asm("nop");
 	    }
@@ -455,6 +468,8 @@ chase_pointers(
 		d = d->next;
 		e = e->next;
 		f = f->next;
+		if (prefetch)
+					prefetch(a->next);
 		for (int64 j=0; j < busy_cycles; j++)
 			asm("nop");
 	    }
@@ -483,6 +498,8 @@ chase_pointers(
 		e = e->next;
 		f = f->next;
 		g = g->next;
+		if (prefetch)
+					prefetch(a->next);
 		for (int64 j=0; j < busy_cycles; j++)
 			asm("nop");
 	    }
@@ -514,6 +531,8 @@ chase_pointers(
 		f = f->next;
 		g = g->next;
 		h = h->next;
+		if (prefetch)
+					prefetch(a->next);
 		for (int64 j=0; j < busy_cycles; j++)
 			asm("nop");
 	    }
@@ -548,6 +567,8 @@ chase_pointers(
 		g = g->next;
 		h = h->next;
 		j = j->next;
+		if (prefetch)
+					prefetch(a->next);
 		for (int64 j=0; j < busy_cycles; j++)
 			asm("nop");
 	    }
@@ -585,6 +606,8 @@ chase_pointers(
 		h = h->next;
 		j = j->next;
 		k = k->next;
+		if (prefetch)
+					prefetch(a->next);
 		for (int64 j=0; j < busy_cycles; j++)
 			asm("nop");
 	    }
@@ -625,6 +648,8 @@ chase_pointers(
 		j = j->next;
 		k = k->next;
 		l = l->next;
+		if (prefetch)
+					prefetch(a->next);
 		for (int64 j=0; j < busy_cycles; j++)
 			asm("nop");
 	    }
@@ -668,6 +693,8 @@ chase_pointers(
 		k = k->next;
 		l = l->next;
 		m = m->next;
+		if (prefetch)
+					prefetch(a->next);
 		for (int64 j=0; j < busy_cycles; j++)
 			asm("nop");
 	    }
@@ -714,6 +741,8 @@ chase_pointers(
 		l = l->next;
 		m = m->next;
 		n = n->next;
+		if (prefetch)
+					prefetch(a->next);
 		for (int64 j=0; j < busy_cycles; j++)
 			asm("nop");
 	    }
@@ -763,6 +792,8 @@ chase_pointers(
 		m = m->next;
 		n = n->next;
 		o = o->next;
+		if (prefetch)
+					prefetch(a->next);
 		for (int64 j=0; j < busy_cycles; j++)
 			asm("nop");
 	    }
@@ -815,6 +846,8 @@ chase_pointers(
 		n = n->next;
 		o = o->next;
 		p = p->next;
+		if (prefetch)
+					prefetch(a->next);
 		for (int64 j=0; j < busy_cycles; j++)
 			asm("nop");
 	    }
@@ -870,6 +903,8 @@ chase_pointers(
 		o = o->next;
 		p = p->next;
 		q = q->next;
+		if (prefetch)
+					prefetch(a->next);
 		for (int64 j=0; j < busy_cycles; j++)
 			asm("nop");
 	    }
@@ -939,7 +974,8 @@ follow_streams(
     int64 bytes_per_line,		// ignored
     int64 bytes_per_chain,		// ignored
     int64 stride,			// ignored
-    int64 busy_cycles	// ignored
+    int64 busy_cycles,	// ignored
+    bool prefetch		// ignored
 )
 {
     int64 refs_per_line  = bytes_per_line  / sizeof(double);