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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"
/**
* 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;
}
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