1 /*---------------------------------------------------------------
2 * Copyright (c) 1999,2000,2001,2002,2003
3 * The Board of Trustees of the University of Illinois
5 *---------------------------------------------------------------
6 * Permission is hereby granted, free of charge, to any person
7 * obtaining a copy of this software (Iperf) and associated
8 * documentation files (the "Software"), to deal in the Software
9 * without restriction, including without limitation the
10 * rights to use, copy, modify, merge, publish, distribute,
11 * sublicense, and/or sell copies of the Software, and to permit
12 * persons to whom the Software is furnished to do
13 * so, subject to the following conditions:
16 * Redistributions of source code must retain the above
17 * copyright notice, this list of conditions and
18 * the following disclaimers.
21 * Redistributions in binary form must reproduce the above
22 * copyright notice, this list of conditions and the following
23 * disclaimers in the documentation and/or other materials
24 * provided with the distribution.
27 * Neither the names of the University of Illinois, NCSA,
28 * nor the names of its contributors may be used to endorse
29 * or promote products derived from this Software without
30 * specific prior written permission.
32 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
33 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
34 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
35 * NONINFRINGEMENT. IN NO EVENT SHALL THE CONTIBUTORS OR COPYRIGHT
36 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
37 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
38 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE
39 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
40 * ________________________________________________________________
41 * National Laboratory for Applied Network Research
42 * National Center for Supercomputing Applications
43 * University of Illinois at Urbana-Champaign
44 * http://www.ncsa.uiuc.edu
45 * ________________________________________________________________
48 * by Mark Gates <mgates@nlanr.net>
49 * -------------------------------------------------------------------
50 * accurate microsecond delay
51 * ------------------------------------------------------------------- */
53 #include "Timestamp.hpp"
57 /* -------------------------------------------------------------------
58 * A micro-second delay function.
59 * ------------------------------------------------------------------- */
60 void delay_loop(unsigned long usec)
62 #ifdef SLEEP_VIA_SELECT
63 // This is a hack but works apparently quite well
64 // I found that it sometimes under-estimates the timeout
70 select(1, (fd_set *) 0, (fd_set *) 0, (fd_set *) 0, &tv);
71 #elif defined(SLEEP_OLD_METHOD)
72 /* Tis uses gettimeofday (underneath the Timestamp), which has a
73 * resolution of upto microseconds. I've found it's good to within
74 * about 10 usecs. I used to do calibration, but iperf automatically
75 * adjusts itself so that isn't necesary, and it causes some problems
76 * if the calibration adjustment is larger than your sleep time.
77 * Note: I found this has problems - if the loop gets interrupted,
78 * long sleeps can result. I found up to 50..60msec. -- Gerrit */
80 end.add( usec * 1e-6 );
83 while ( now.before( end ) ) {
87 // This is preferred; it is even better than usleep (see manpage).
91 ts.tv_nsec = usec * 1000L;
93 if (nanosleep(&ts, NULL) < 0)
94 WARN_errno(1, "nanosleep");