1 files changed, 93 insertions, 0 deletions
diff --git a/progs/perf/common.c b/progs/perf/common.c
new file mode 100644
index 0000000000..a50fc11cca
--- /dev/null
+++ b/progs/perf/common.c
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2009  VMware, Inc.  All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * VMWARE BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+/**
+ * Common perf code.  This should be re-usable with other APIs.
+ */
+
+#include "common.h"
+#include "glmain.h"
+
+
+/**
+ * Run function 'f' for enough iterations to reach a steady state.
+ * Return the rate (iterations/second).
+ */
+double
+PerfMeasureRate(PerfRateFunc f)
+{
+   const double minDuration = 1.0;
+   double rate = 0.0, prevRate = 0.0;
+   unsigned subiters;
+
+   /* Compute initial number of iterations to try.
+    * If the test function is pretty slow this helps to avoid
+    * extraordarily long run times.
+    */
+   subiters = 2;
+   {
+      const double t0 = PerfGetTime();
+      double t1;
+      do {
+         f(subiters); /* call the rendering function */
+         t1 = PerfGetTime();
+         subiters *= 2;
+      } while (t1 - t0 < 0.1 * minDuration);
+   }
+   /*printf("initial subIters = %u\n", subiters);*/
+
+   while (1) {
+      const double t0 = PerfGetTime();
+      unsigned iters = 0;
+      double t1;
+
+      do {
+         f(subiters); /* call the rendering function */
+         t1 = PerfGetTime();
+         iters += subiters;
+      } while (t1 - t0 < minDuration);
+
+      rate = iters / (t1 - t0);
+
+      if (0)
+         printf("prevRate %f  rate  %f  ratio %f  iters %u\n",
+                prevRate, rate, rate/prevRate, iters);
+
+      /* Try and speed the search up by skipping a few steps:
+       */
+      if (rate > prevRate * 1.6)
+         subiters *= 8;
+      else if (rate > prevRate * 1.2)
+         subiters *= 4;
+      else if (rate > prevRate * 1.05)
+         subiters *= 2;
+      else
+         break;
+
+      prevRate = rate;
+   }
+
+   if (0)
+      printf("%s returning iters %u  rate %f\n", __FUNCTION__, subiters, rate);
+   return rate;
+}
+
+