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- /* $Id:$ */
- /*
- * Copyright (c) 2008 Aaron Turner.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- * 3. Neither the names of the copyright owners nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
- * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
- * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
- * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
- * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
- * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
- * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
- * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
- * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
- #include "config.h"
- #include "defines.h"
- #include "common.h"
- #include <sys/types.h>
- #include <errno.h>
- #include <string.h>
- #include <stdlib.h>
- #include <unistd.h>
- /*
- * returns the # of clicks/usec
- */
- u_int64_t
- rdtsc_calibrate(u_int32_t mhz)
- {
- static u_int64_t x = 0;
- u_int64_t v = 0;
- struct timeval start, end, diff;
- u_int64_t x1, x2;
- u_int16_t n;
-
- if (x != 0) {
- return x;
- } else if (mhz > 0 && x == 0) {
- x = (u_int64_t)mhz;
- notice("Using user specification of %llu Mhz", x);
- } else {
- /* haven't calculated clicks/usec yet */
- for (n=0; n<16; ++n) {
- gettimeofday(&start, 0);
- x1 = rdtsc();
- usleep(100000);
- x2 = rdtsc();
- gettimeofday(&end, 0);
- timersub(&end, &start, &diff);
- v = (x2 - x1)/(diff.tv_sec * 1000000 + diff.tv_usec);
- x = x ? (x + v)/2 : v;
- }
- notice("Using guessimate of %llu Mhz", x);
- }
- return x;
- }
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