gcc-plugin: add a very simple stencil example

gcc-plugin/examples/Makefile.am

@@ -14,7 +14,7 @@
 # See the GNU Lesser General Public License in COPYING.LGPL for more details.
 
 noinst_PROGRAMS =				\
-  matrix-mult
+  matrix-mult stencil5
 
 AM_LDFLAGS = $(top_builddir)/src/libstarpu.la
 

gcc-plugin/examples/stencil5.c

@@ -0,0 +1,127 @@
+/* StarPU --- Runtime system for heterogeneous multicore architectures.
+ *
+ * Copyright (C) 2011  Centre National de la Recherche Scientifique
+ *
+ * StarPU is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or (at
+ * your option) any later version.
+ *
+ * StarPU is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * See the GNU Lesser General Public License in COPYING.LGPL for more details.
+ */
+
+#include <stdlib.h>
+#include <math.h>
+
+#ifndef STARPU_GCC_PLUGIN
+# error must be compiled with the StarPU GCC plug-in
+#endif
+
+/* Definition of the StarPU task and its CPU implementation.  */
+static void stencil5(float *xy, const float *xm1y, const float *xp1y, const float *xym1, const float *xyp1)
+	__attribute__ ((task));
+
+static void stencil5_cpu(float *xy, const float *xm1y, const float *xp1y, const float *xym1, const float *xyp1)
+	__attribute__ ((task_implementation ("cpu", stencil5)));
+
+static void stencil5_cpu(float *xy, const float *xm1y, const float *xp1y, const float *xym1, const float *xyp1)
+{
+	*xy = (*xy + *xm1y + *xp1y + *xym1 + *xyp1) / 5;
+}
+
+#define NITER_DEF 20000
+#define X         10
+#define Y         10
+
+int display = 0;
+int niter = NITER_DEF;
+
+static void parse_args(int argc, char **argv)
+{
+	int i;
+	for (i = 1; i < argc; i++) {
+		if (strcmp(argv[i], "-iter") == 0) {
+			char *argptr;
+			niter = strtol(argv[++i], &argptr, 10);
+		}
+		if (strcmp(argv[i], "-display") == 0) {
+			display = 1;
+		}
+	}
+}
+
+static float my_rand (void)
+{
+	return (float) rand () / (float) RAND_MAX;
+}
+
+int main(int argc, char **argv)
+{
+        int x, y;
+        float mean=0;
+        float matrix[X][Y];
+
+        parse_args(argc, argv);
+
+	srand (time (NULL));
+        for(x = 0; x < X; x++) {
+                for (y = 0; y < Y; y++) {
+                        matrix[x][y] = my_rand () * 100;
+                        mean += matrix[x][y];
+                }
+        }
+        mean /= (x*y);
+
+        if (display) {
+                fprintf(stdout, "mean=%f\n", mean);
+                for(x = 0; x < X; x++) {
+                        for (y = 0; y < Y; y++) {
+                                fprintf(stdout, "%3f ", matrix[x][y]);
+                        }
+                        fprintf(stdout, "\n");
+                }
+        }
+
+#pragma starpu initialize
+
+        for(x = 0; x < X; x++) {
+		for (y = 0; y < Y; y++) {
+#pragma starpu register &matrix[x][y] 1
+		}
+	}
+
+	while(niter--) {
+                for (x = 1; x < X-1; x++) {
+                        for (y = 1; y < Y-1; y++) {
+                                stencil5(&matrix[x][y], &matrix[x-1][y], &matrix[x+1][y],
+					 &matrix[x][y-1], &matrix[x][y+1]);
+                        }
+                }
+        }
+
+#pragma starpu wait
+
+        for(x = 0; x < X; x++) {
+                for (y = 0; y < Y; y++) {
+#pragma starpu unregister &matrix[x][y]
+                }
+        }
+
+#pragma starpu shutdown
+
+        if (display) {
+                fprintf(stdout, "mean=%f\n", mean);
+                for(x = 0; x < X; x++) {
+                        for (y = 0; y < Y; y++) {
+                                fprintf(stdout, "%3f ", matrix[x][y]);
+                        }
+                        fprintf(stdout, "\n");
+                }
+        }
+
+	return EXIT_SUCCESS;
+}