benchmark on pentium stuff

wrlib/bench.h

@@ -0,0 +1,68 @@
+
+
+
+inline static void
+cycle_bench(int start) 
+{
+    static volatile unsigned int start_cycle;
+    
+    if (start) {
+	asm volatile
+	    ("pushl %%edx	\n\t"
+	     "rdtsc         	\n\t"
+	     "movl %%eax,%0  	\n\t"
+	     "cld            	\n\t"
+	     "popl %%edx	\n\t"
+	     "nop            	\n\t"
+	     "nop            	\n\t"
+	     "nop            	\n\t"
+	     "nop            	\n\t"
+	     "nop            	\n\t"
+	     "nop       	\n\t"
+	     "nop            	\n\t"
+	     "nop    	        \n\t"
+	     : "=m" (start_cycle) : : "eax", "edx");
+    } else {
+	volatile int end;
+	
+	asm volatile
+	    ("pushl %%edx	\n\t"
+	     "clc            	\n\t"
+	     "rdtsc          	\n\t"
+	     "movl %%eax, %0	\n\t"
+	     "popl %%edx	\n\t"
+	     : "=m" (end) : : "eax", "edx");
+	
+	printf("Cycle count = %u\n", end - start_cycle - 68);
+    }
+}
+
+
+
+#if 0
+// seems linux doesnt allow user progs to exec rdpcm..
+inline static void
+cache_bench(int start) 
+{
+    static int start_cycle;
+    
+    if (start) {
+	asm volatile(
+		"movl $1,%%ecx	\n\t"
+		"rdpmc         \n\t"
+		"movl %%eax,%0  \n\t"
+                 : "=m" (start_cycle));
+    } else {
+	int end;
+	
+	asm volatile(
+		"movl $1,%%ecx	\n\t"
+                "rdpmc          \n\t"
+                "movl %%eax,%0"
+                 : "=m" (end));
+	
+	printf("Cache reloads counted = %i\n", end - start_cycle);
+    }
+}
+
+#endif