1 /* -----------------------------------------------------------------------------
2 * $Id: Itimer.c,v 1.13 2000/04/03 15:54:49 simonmar Exp $
4 * (c) The GHC Team, 1995-1999
6 * Interval timer for profiling and pre-emptive scheduling.
8 * ---------------------------------------------------------------------------*/
11 * The interval timer is used for profiling and for context switching in the
12 * threaded build. Though POSIX 1003.1b includes a standard interface for
13 * such things, no one really seems to be implementing them yet. Even
14 * Solaris 2.3 only seems to provide support for @CLOCK_REAL@, whereas we're
15 * keen on getting access to @CLOCK_VIRTUAL@.
17 * Hence, we use the old-fashioned @setitimer@ that just about everyone seems
18 * to support. So much for standards.
22 # define NON_POSIX_SOURCE
27 #include "Proftimer.h"
30 /* As recommended in the autoconf manual */
31 # ifdef TIME_WITH_SYS_TIME
32 # include <sys/time.h>
35 # ifdef HAVE_SYS_TIME_H
36 # include <sys/time.h>
50 #if defined(mingw32_TARGET_OS) || (defined(cygwin32_TARGET_OS) && !defined(HAVE_SETITIMER))
53 handle_tick(int unused STG_UNUSED);
55 /* -----------------------------------------------------------------------------
58 We use the ticker for two things: supporting threadDelay, and time
61 SMP note: this signal could be delivered to *any* thread. We have
62 to ensure that it doesn't matter which thread actually runs the
64 -------------------------------------------------------------------------- */
68 #if defined(mingw32_TARGET_OS) || (defined(cygwin32_TARGET_OS) && !defined(HAVE_SETITIMER))
71 handle_tick(int unused STG_UNUSED)
79 /* For threadDelay etc., see Select.c */
85 * Handling timer events under cygwin32 is not done with signal/setitimer.
86 * Instead of the two steps of first registering a signal handler to handle
87 * \tr{SIGVTALRM} and then start generating them via @setitimer()@, we use
88 * the Multimedia API (MM) and its @timeSetEvent@. (Internally, the MM API
89 * creates a separate thread that will notify the main thread of timer
90 * expiry). -- SOF 7/96
92 * 11/98: if the cygwin DLL supports setitimer(), then use it instead.
95 #if defined(mingw32_TARGET_OS) || (defined(cygwin32_TARGET_OS) && !defined(HAVE_SETITIMER))
98 * Sigh - to avoid requiring anyone that wants to build ghc to have
99 * to augment the Win32 header files that comes with cygwinb20.1,
100 * include the missing MM API decls here inline.
102 * ToDo: check and remove these once the next version of cygwin is
105 #define TIMERR_NOERROR 0
106 #define TIMERR_NOCANDO 97
107 #define TIME_PERIODIC 1
109 typedef UINT MMRESULT;
110 typedef void CALLBACK (*TIMECALLBACK) (UINT, UINT, DWORD, DWORD, DWORD);
111 typedef TIMECALLBACK *LPTIMECALLBACK;
112 MMRESULT STDCALL timeSetEvent(UINT, UINT, LPTIMECALLBACK, DWORD, UINT);
114 vtalrm_handler is assigned and set up in Signals.c
116 vtalrm_id (defined in Signals.c) holds
117 the system id for the current timer (used to
118 later block/kill it.)
120 extern nat vtalrm_id;
121 TIMECALLBACK *vtalrm_cback;
124 initialize_virtual_timer(nat ms)
127 /* On Win32 setups that don't have support for
128 setitimer(), we use the MultiMedia API's timer
131 As the delivery of ticks isn't free, we only
132 enable it if we really needed, i.e., when profiling.
133 (the RTS now also needs timer ticks to implement
134 threadDelay in non-profiling mode, but the pure
135 Win32 port doesn't support that.....yet.)
137 unsigned int delay,vtalrm_id;
139 delay = timeBeginPeriod(1);
140 if (delay == TIMERR_NOCANDO) { /* error of some sort. */
144 timeSetEvent(ms, /* event every `delay' milliseconds. */
145 1, /* precision is within 5 millisecs. */
146 (LPTIMECALLBACK)vtalrm_cback,
156 initialize_virtual_timer(nat ms)
158 # ifndef HAVE_SETITIMER
159 /* fprintf(stderr, "No virtual timer on this system\n"); */
164 it.it_value.tv_sec = ms / 1000;
165 it.it_value.tv_usec = 1000 * (ms - (1000 * it.it_value.tv_sec));
166 it.it_interval = it.it_value;
167 return (setitimer(ITIMER_VIRTUAL, &it, NULL));
171 #endif /* !cygwin32_TARGET_OS */
174 /* This is a potential POSIX version */
176 initialize_virtual_timer(nat ms)
179 struct itimerspec it;
182 se.sigev_notify = SIGEV_SIGNAL;
183 se.sigev_signo = SIGVTALRM;
184 se.sigev_value.sival_int = SIGVTALRM;
185 if (timer_create(CLOCK_VIRTUAL, &se, &tid)) {
186 barf("can't create virtual timer");
188 it.it_value.tv_sec = ms / 1000;
189 it.it_value.tv_nsec = 1000000 * (ms - 1000 * it.it_value.tv_sec);
190 it.it_interval = it.it_value;
191 timer_settime(tid, TIMER_RELTIME, &it, NULL);
195 #if defined(mingw32_TARGET_OS) || (defined(cygwin32_TARGET_OS) && !defined(HAVE_SETITIMER))
197 install_vtalrm_handler(void)
199 vtalrm_cback = handle_tick;
205 install_vtalrm_handler(void)
207 struct sigaction action;
209 action.sa_handler = handle_tick;
211 sigemptyset(&action.sa_mask);
214 return sigaction(SIGVTALRM, &action, NULL);
218 block_vtalrm_signal(void)
222 sigemptyset(&signals);
223 sigaddset(&signals, SIGVTALRM);
225 (void) sigprocmask(SIG_BLOCK, &signals, NULL);
229 unblock_vtalrm_signal(void)
233 sigemptyset(&signals);
234 sigaddset(&signals, SIGVTALRM);
236 (void) sigprocmask(SIG_UNBLOCK, &signals, NULL);
240 #if !defined(HAVE_SETITIMER) && !defined(mingw32_TARGET_OS)
242 getourtimeofday(void)
245 gettimeofday(&tv, (struct timezone *) NULL);
246 return (tv.tv_sec * 1000000 + tv.tv_usec);