1 files changed, 108 insertions, 0 deletions
diff --git a/Carpet/CycleClock/src/cycle.cc b/Carpet/CycleClock/src/cycle.cc
new file mode 100644
index 000000000..3a6b48364
--- /dev/null
+++ b/Carpet/CycleClock/src/cycle.cc
@@ -0,0 +1,108 @@
+#include "cycleclock.h"
+
+#include <cctk.h>
+
+
+
+// Find a good wall clock timer
+#ifdef _OPENMP
+#  include <omp.h>
+#endif
+#ifdef HAVE_CAPABILITY_MPI
+#  include <mpi.h>
+#endif
+#ifdef HAVE_SYS_TIME_H
+#  include <sys/time.h>
+#endif
+
+
+
+static double cycleclock_tick = -1.0; // uninitialised
+
+
+
+#ifdef HAVE_SYS_TIME_H
+static double get_sys_time()
+{
+  timeval tp;
+  gettimeofday(&tp, NULL);
+  return tp.tv_sec + 1.0e-6 * tp.tv_usec;
+}
+#endif
+
+
+
+void measure_tick()
+{
+  // Make a few warm-up measurements
+  getticks();
+  getticks();
+  getticks();
+  
+#ifdef _OPENMP
+  if (cycleclock_tick < 0.0) {
+    // Use omp_get_sys_time to calibrate the timer
+    CCTK_INFO("Measuring CycleClock tick via OpenMP...");
+    ticks const rstart = getticks();
+    double const wstart = omp_get_wtime();
+    while (omp_get_wtime() < wstart + 1.0) {
+      // do nothing, just wait
+    }
+    ticks const rend = getticks();
+    double const wend = omp_get_wtime();
+    cycleclock_tick = (wend - wstart) / elapsed(rend, rstart);
+  }
+#endif
+  
+#ifdef HAVE_CAPABILITY_MPI
+  if (cycleclock_tick < 0.0) {
+    // Use MPI_Wtime to calibrate the timer
+    CCTK_INFO("Measuring CycleClock tick via MPI...");
+    ticks const rstart = getticks();
+    double const wstart = MPI_Wtime();
+    while (MPI_Wtime() < wstart + 1.0) {
+        // do nothing, just wait
+    }
+    ticks const rend = getticks();
+    double const wend = MPI_Wtime();
+    cycleclock_tick = (wend - wstart) / elapsed(rend, rstart);
+  }
+#endif
+  
+#ifdef HAVE_SYS_TIME_H
+  if (cycleclock_tick < 0.0) {
+    // Use gettimeofday to calibrate the timer
+    CCTK_INFO("Measuring CycleClock tick via gettimeofday...");
+    ticks const rstart = getticks();
+    double const wstart = get_sys_time();
+    while (get_sys_time() < wstart + 1.0) {
+      // do nothing, just wait
+    }
+    ticks const rend = getticks();
+    double const wend = get_sys_time();
+    cycleclock_tick = (wend - wstart) / elapsed(rend, rstart);
+  }
+#endif
+  
+  if (cycleclock_tick < 0.0) {
+    // Give up; just set the time scale to 1
+    CCTK_INFO("Could not measure CycleClock tick");
+    cycleclock_tick = 1.0;
+  }
+  
+  CCTK_VInfo(CCTK_THORNSTRING,
+             "Calibrated CycleClock: %g ns per clock tick (%g GHz)",
+             1.0e9 * cycleclock_tick, 1.0e-9 / cycleclock_tick);
+}
+
+
+
+double seconds_per_tick()
+{
+  // if (CCTK_BUILTIN_EXPECT(cycleclock_tick < 0.0, false)) {
+  //   CCTK_WARN(CCTK_WARN_ALERT,
+  //             "Thorn CycleClock has not been activated; the first measurements may be wrong");
+  //   measure_tick();
+  // }
+  return cycleclock_tick;
+}