/* -*- indent-tabs-mode:T; c-basic-offset:8; tab-width:8; -*- vi: set ts=8: * $Id: timer.h,v 2.0 2002/09/22 02:07:31 tramm Exp $ * * (c) Trammell Hudson * * High performance timing functions * ************* * *  This file is part of the autopilot simulation package. * *  For more details: * *	http://autopilot.sourceforge.net/ * *  Autopilot is free software; you can redistribute it and/or modify *  it under the terms of the GNU General Public License as published by *  the Free Software Foundation; either version 2 of the License, or *  (at your option) any later version. * *  Autopilot is distributed in the hope that it will be useful, *  but WITHOUT ANY WARRANTY; without even the implied warranty of *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the *  GNU General Public License for more details. * *  You should have received a copy of the GNU General Public License *  along with Autopilot; if not, write to the Free Software *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA * */#ifndef _TIMER_H_#define _TIMER_H_#include <stdio.h>#include <sys/time.h>typedef struct timeval stopwatch_t;/** *  Inline functions to help keep track of time. * This one starts a stopwatch. */static voidstart(	stopwatch_t *		t){	gettimeofday( t, 0 );}/** *  This one stops a stopwatch and returns the number of microseconds * since the timer was started.  It is safe to call it multiple times * with the same stopwatch_t, so you can use it like a lap counter, too. */static unsigned longstop(	stopwatch_t *		t){	stopwatch_t		end;	gettimeofday( &end, 0 );	while( end.tv_sec > t->tv_sec )	{		end.tv_sec --;		end.tv_usec += 1000000;	}	return end.tv_usec - t->tv_usec;}/** *  Handy macro to compare the runtimes (and perhaps efficiency) * of two similar procedures.  Inspired by the Perl 'use Benchmark' * module. */#define time_these( iters, name1, block1, name2, block2 )		\	do {								\		stopwatch_t		timer;				\		const unsigned long	_iters = iters;			\		unsigned long		time1;				\		unsigned long		time2;				\									\		printf( "\nTiming %lu iterations of %s and %s\n",	\			_iters,						\			name1,						\			name2						\		);							\									\		start( &timer );					\		for( unsigned long i = 0 ; i < _iters ; i++ )		\		{							\			block1;						\		}							\		time1 = stop( &timer );					\									\		start( &timer );					\		for( unsigned long i = 0 ; i < _iters ; i++ )		\		{							\			block2;						\		}							\		time2 = stop( &timer );					\									\		double	time_per1 = (double)time1 / (double)_iters;	\		double	time_per2 = (double)time2 / (double)_iters;	\									\		printf( "%s: Total = %lu => %lf usec each\n",		\			name1,						\			time1,						\			time_per1					\		);							\									\		printf( "%s: Total = %lu => %lf usec each\n",		\			name2,						\			time2,						\			time_per2					\		);							\									\		printf( "%3.3lf%% change\n",				\			100.0 * (time_per1 - time_per2) / time_per2	\		);							\	} while(0)							\#endif