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-rw-r--r--progs/perf/common.c115
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diff --git a/progs/perf/common.c b/progs/perf/common.c
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+/*
+ * 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"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+
+
+/* Need to add a fflush windows console with mingw, otherwise nothing
+ * shows up until program exit. May want to add logging here.
+ */
+void
+perf_printf(const char *format, ...)
+{
+ va_list ap;
+ va_start(ap, format);
+
+ fflush(stdout);
+ vfprintf(stdout, format, ap);
+ fflush(stdout);
+
+ va_end(ap);
+}
+
+
+
+/**
+ * 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);
+ }
+ /*perf_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)
+ perf_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)
+ perf_printf("%s returning iters %u rate %f\n", __FUNCTION__, subiters, rate);
+ return rate;
+}
+
+