mirror of https://github.com/CGAL/cgal
138 lines
4.4 KiB
C++
138 lines
4.4 KiB
C++
// Copyright (c) 1997 Utrecht University (The Netherlands),
|
|
// ETH Zurich (Switzerland), Freie Universitaet Berlin (Germany),
|
|
// INRIA Sophia-Antipolis (France), Martin-Luther-University Halle-Wittenberg
|
|
// (Germany), Max-Planck-Institute Saarbruecken (Germany), RISC Linz (Austria),
|
|
// and Tel-Aviv University (Israel). All rights reserved.
|
|
//
|
|
// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
|
|
// modify it under the terms of the GNU Lesser General Public License as
|
|
// published by the Free Software Foundation; version 2.1 of the License.
|
|
// See the file LICENSE.LGPL distributed with CGAL.
|
|
//
|
|
// Licensees holding a valid commercial license may use this file in
|
|
// accordance with the commercial license agreement provided with the software.
|
|
//
|
|
// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
|
|
// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
|
|
//
|
|
// $URL$
|
|
// $Id$
|
|
//
|
|
//
|
|
// Author(s) : Lutz Kettner <kettner@inf.ethz.ch>
|
|
// Matthias Baesken <baesken@informatik.uni-halle.de>
|
|
|
|
#include <CGAL/Timer.h>
|
|
|
|
// Determine if the POSIX function getrusage is available, otherwise
|
|
// use the previous solution based on std::clock().
|
|
// First, detect POSIX. We cannot reliably use "unistd.h",
|
|
// but limits.h is part of the C standard.
|
|
#include <climits>
|
|
#ifdef _POSIX_ARG_MAX // now that should be POSIX
|
|
#include <unistd.h>
|
|
#ifdef _POSIX_VERSION
|
|
#ifdef _XOPEN_UNIX // XSI: X/Open System Interfaces Extension
|
|
#define CGAL__GETRUSAGE 1
|
|
#endif
|
|
#endif
|
|
#endif
|
|
|
|
|
|
#ifdef CGAL__GETRUSAGE
|
|
// types, function prototype and constants for the POSIX function
|
|
// int getrusage (int who, struct rusage *usage);
|
|
#include <sys/resource.h>
|
|
// For the numerical limits
|
|
#else // CGAL__GETRUSAGE //
|
|
// used for clock()
|
|
#include <ctime>
|
|
#endif // CGAL__GETRUSAGE //
|
|
|
|
// For the numerical limits
|
|
#include <float.h>
|
|
|
|
|
|
CGAL_BEGIN_NAMESPACE
|
|
|
|
|
|
// Static member variable for Timer
|
|
// =====================================
|
|
|
|
bool Timer::m_failed = false;
|
|
|
|
// Member functions for Timer
|
|
// =====================================
|
|
|
|
double Timer::user_process_time() const {
|
|
// Depends on the operating system.
|
|
// Returns a (weakly ;-) monotone increasing time in seconds (with
|
|
// possible wrap-around in case of overflow, see max()), or 0.0
|
|
// if the system call for the time failed. If the system call
|
|
// failed the static flag 'm_failed' is set and can be used
|
|
// by the caller.
|
|
#ifdef CGAL__GETRUSAGE
|
|
struct rusage usage;
|
|
int ret = getrusage( RUSAGE_SELF, &usage);
|
|
CGAL_warning_msg( ret == 0, "Call to getrusage() in class CGAL::Timer "
|
|
"failed - timings will be 0.");
|
|
if ( ret == 0) {
|
|
return double( usage.ru_utime.tv_sec) // seconds
|
|
+ double( usage.ru_utime.tv_usec) / 1000000.0; // microseconds
|
|
}
|
|
#else // CGAL__GETRUSAGE //
|
|
CGAL_CLIB_STD::clock_t clk = CGAL_CLIB_STD::clock();
|
|
CGAL_warning_msg( clk != (CGAL_CLIB_STD::clock_t)-1,
|
|
"Call to clock() in class CGAL::Timer failed - timings will be 0.");
|
|
if ( clk != (CGAL_CLIB_STD::clock_t)-1) {
|
|
return double(clk) / CLOCKS_PER_SEC;
|
|
}
|
|
#endif // CGAL__GETRUSAGE //
|
|
m_failed = true;
|
|
return 0.0;
|
|
}
|
|
|
|
double Timer::compute_precision() const {
|
|
// Computes timer precision in seconds dynamically. Note that
|
|
// the timer system call is probably non-trivial and will show
|
|
// up in this time here (probably for one call). But that is just
|
|
// fine that the call to the timer itself if reported as noise
|
|
// in the precision.
|
|
double min_res = DBL_MAX;
|
|
for ( int i = 0; i < 5; ++i) {
|
|
double current = user_process_time();
|
|
if ( m_failed)
|
|
return -1.0;
|
|
double next = user_process_time();
|
|
while ( current >= next) { // wait until timer increases
|
|
next = user_process_time();
|
|
if ( m_failed)
|
|
return -1.0;
|
|
}
|
|
// Get the minimum timing difference of all runs.
|
|
if ( min_res > next - current)
|
|
min_res = next - current;
|
|
}
|
|
return min_res;
|
|
}
|
|
|
|
double Timer::precision() const {
|
|
// computes precision upon first call
|
|
// returns -1.0 if timer system call fails.
|
|
static double prec = compute_precision();
|
|
return prec;
|
|
}
|
|
|
|
double Timer::max() const {
|
|
// Depends on the operating system.
|
|
#ifdef CGAL__GETRUSAGE
|
|
return DBL_MAX;
|
|
#else // CGAL__GETRUSAGE //
|
|
return 2146.0;
|
|
#endif // CGAL__GETRUSAGE //
|
|
}
|
|
|
|
CGAL_END_NAMESPACE
|
|
|
|
// EOF //
|