supercop-20100803

cpucycles/amd64cpuinfo.c

@@ -1,5 +1,6 @@
 #include <stdio.h>
 #include <sys/types.h>
+#include "osfreq.c"
 
 long long cpucycles_amd64cpuinfo(void)
 {
@@ -11,20 +12,5 @@ long long cpucycles_amd64cpuinfo(void)
 
 long long cpucycles_amd64cpuinfo_persecond(void)
 {
-  FILE *f;
-  double result;
-  int s;
-
-  f = fopen("/proc/cpuinfo","r");
-  if (!f) return 0;
-
-  for (;;) {
-    s = fscanf(f,"cpu MHz : %lf",&result);
-    if (s > 0) break;
-    if (s == 0) s = fscanf(f,"%*[^\n]\n");
-    if (s < 0) { result = 0; break; }
-  }
-
-  fclose(f);
-  return 1000000.0 * result;
+  return osfreq();
 }

cpucycles/amd64cpuinfo.h

@@ -1,5 +1,5 @@
 /*
-cpucycles amd64cpuinfo.h version 20060318
+cpucycles amd64cpuinfo.h version 20100803
 D. J. Bernstein
 Public domain.
 */

cpucycles/celllinux.c

@@ -4,6 +4,7 @@
 #include <sys/time.h>
 #include <sys/types.h>
 #include <spu_mfcio.h>
+#include "osfreq.c"
 
 static long myround(double u)
 {
@@ -49,27 +50,14 @@ static double guesstbcycles(void)
 
 static void init(void)
 {
-  FILE *f;
-  int s;
   int loop;
   double guess1;
   double guess2;
 
   spu_write_decrementer(0xffffffff);
 
-  f = fopen("/proc/cpuinfo","r");
-  if (!f) return;
-
-  for (;;) {
-    s = fscanf(f," clock : %lf MHz",&cpufrequency);
-    if (s > 0) break;
-    if (s == 0) s = fscanf(f,"%*[^\n]\n");
-    if (s < 0) { cpufrequency = 0; break; }
-  }
-
-  fclose(f);
+  cpufrequency = osfreq();
   if (!cpufrequency) return;
-  cpufrequency *= 1000000.0;
 
   for (loop = 0;loop < 100;++loop) {
     guess1 = guesstbcycles();

cpucycles/dev4ns.c

@@ -0,0 +1,62 @@
+#include <sys/types.h>
+#include <fcntl.h>
+#include <time.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/time.h>
+
+static int fddev = -1;
+static int prev[3];
+static unsigned long long prevcycles = 0;
+static int now[3];
+static long long cyclespersec = 0;
+
+static void readdev(unsigned int *result)
+{
+  if (read(fddev,result,12) == 12) return;
+  result[0] = result[1] = result[2] = 0;
+}
+
+long long cpucycles_dev4ns(void)
+{
+  unsigned long long delta4;
+  int deltan;
+  int deltas;
+  unsigned long long guesscycles;
+
+  if (fddev == -1) {
+    fddev = open("/dev/cpucycles4ns",O_RDONLY);
+    readdev(prev);
+  }
+
+  readdev(now);
+  delta4 = (unsigned int) (now[0] - prev[0]); /* unsigned change in number of cycles mod 2^32 */
+  deltan = now[1] - prev[1]; /* signed change in number of nanoseconds mod 10^9 */
+  deltas = now[2] - prev[2]; /* signed change in number of seconds */
+  if ((deltas == 0 && deltan < 200000000) || (deltas == 1 && deltan < -800000000))
+    return prevcycles + delta4;
+
+  prev[0] = now[0];
+  prev[1] = now[1];
+  prev[2] = now[2];
+
+  if ((deltas == 0 && deltan < 300000000) || (deltas == 1 && deltan < -700000000)) {
+    // actual number of cycles cannot have increased by 2^32 in <0.3ms
+    cyclespersec = 1000000000 * (unsigned long long) delta4;
+    cyclespersec /= deltan + 1000000000 * (long long) deltas;
+  } else {
+    guesscycles = deltas * cyclespersec;
+    guesscycles += (deltan * cyclespersec) / 1000000000;
+    while (delta4 + 2147483648ULL < guesscycles) delta4 += 4294967296ULL;
+    /* XXX: could do longer-term extrapolation here */
+  }
+
+  prevcycles += delta4;
+  return prevcycles;
+}
+
+long long cpucycles_dev4ns_persecond(void)
+{
+  while (!cyclespersec) cpucycles_dev4ns();
+  return cyclespersec;
+}

cpucycles/dev4ns.h

@@ -0,0 +1,27 @@
+/*
+cpucycles dev4ns.h version 20100803
+D. J. Bernstein
+Public domain.
+*/
+
+#ifndef CPUCYCLES_dev4ns_h
+#define CPUCYCLES_dev4ns_h
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern long long cpucycles_dev4ns(void);
+extern long long cpucycles_dev4ns_persecond(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#ifndef cpucycles_implementation
+#define cpucycles_implementation "dev4ns"
+#define cpucycles cpucycles_dev4ns
+#define cpucycles_persecond cpucycles_dev4ns_persecond
+#endif
+
+#endif