libc/gen/clock.c

1.9       dsl /*	$NetBSD: clock.c,v 1.9 2003/08/19 08:31:18 dsl Exp $	*/
1.5       cgd
1.1       cgd /*
1.5       cgd  * Copyright (c) 1989, 1993
1.5       cgd  *	The Regents of the University of California.  All rights reserved.
1.1       cgd  *
1.1       cgd  * Redistribution and use in source and binary forms, with or without
1.1       cgd  * modification, are permitted provided that the following conditions
1.1       cgd  * are met:
1.1       cgd  * 1. Redistributions of source code must retain the above copyright
1.1       cgd  *    notice, this list of conditions and the following disclaimer.
1.1       cgd  * 2. Redistributions in binary form must reproduce the above copyright
1.1       cgd  *    notice, this list of conditions and the following disclaimer in the
1.1       cgd  *    documentation and/or other materials provided with the distribution.
1.8       agc  * 3. Neither the name of the University nor the names of its contributors
1.1       cgd  *    may be used to endorse or promote products derived from this software
1.1       cgd  *    without specific prior written permission.
1.1       cgd  *
1.1       cgd  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
1.1       cgd  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
1.1       cgd  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
1.1       cgd  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
1.1       cgd  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
1.1       cgd  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
1.1       cgd  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
1.1       cgd  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
1.1       cgd  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
1.1       cgd  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
1.1       cgd  * SUCH DAMAGE.
1.1       cgd  */
1.1       cgd
1.6  christos #include <sys/cdefs.h>
1.1       cgd #if defined(LIBC_SCCS) && !defined(lint)
1.5       cgd #if 0
1.5       cgd static char sccsid[] = "@(#)clock.c	8.1 (Berkeley) 6/4/93";
1.5       cgd #else
1.9       dsl __RCSID("$NetBSD: clock.c,v 1.9 2003/08/19 08:31:18 dsl Exp $");
1.5       cgd #endif
1.1       cgd #endif /* LIBC_SCCS and not lint */
1.1       cgd
1.1       cgd #include <sys/param.h>
1.1       cgd #include <sys/time.h>
1.1       cgd #include <sys/resource.h>
1.7    kleink
1.7    kleink #include <time.h>
1.1       cgd
1.1       cgd /*
1.9       dsl  * This code is all rather silly because the kernel counts actual
1.9       dsl  * execution time (to usec accuracy) then splits it into user, system and
1.9       dsl  * interrupt based on when clock ticks happen.  getrusage apportions the
1.9       dsl  * time based on the number of ticks, and here we are trying to generate
1.9       dsl  * a number which was, traditionally, the number of ticks!
1.9       dsl  *
1.9       dsl  * Due to the way the time is apportioned, this code (and indeed getrusage
1.9       dsl  * itself) are not guaranteed monotonic.
1.1       cgd  */
1.1       cgd
1.1       cgd clock_t
1.1       cgd clock()
1.1       cgd {
1.1       cgd 	struct rusage ru;
1.9       dsl 	clock_t hz = CLOCKS_PER_SEC;
1.1       cgd
1.1       cgd 	if (getrusage(RUSAGE_SELF, &ru))
1.1       cgd 		return ((clock_t) -1);
1.9       dsl 	return (ru.ru_utime.tv_sec + ru.ru_stime.tv_sec) * hz +
1.9       dsl 	    (ru.ru_utime.tv_usec + ru.ru_stime.tv_usec + 50) / 100 * hz / 10000;
1.1       cgd }