X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Frts%2FItimer.c;h=50be88dd799a68605bb14085b69b9d21db44e2c2;hb=ea45357425c27c2d46c8d0e70c2fa4767d941f44;hp=d40ab4e7c4e123c3c6b19d1026baf3ac1f5fbb5d;hpb=7f309f1c021e7583f724cce599ce2dd3c439361b;p=ghc-hetmet.git diff --git a/ghc/rts/Itimer.c b/ghc/rts/Itimer.c index d40ab4e..50be88d 100644 --- a/ghc/rts/Itimer.c +++ b/ghc/rts/Itimer.c @@ -1,5 +1,4 @@ /* ----------------------------------------------------------------------------- - * $Id: Itimer.c,v 1.3 1999/02/05 16:02:44 simonm Exp $ * * (c) The GHC Team, 1995-1999 * @@ -17,13 +16,12 @@ * Hence, we use the old-fashioned @setitimer@ that just about everyone seems * to support. So much for standards. */ - -#if !defined(_AIX) -# define NON_POSIX_SOURCE -#endif - #include "Rts.h" +#include "RtsFlags.h" +#include "Timer.h" #include "Itimer.h" +#include "Proftimer.h" +#include "Schedule.h" /* As recommended in the autoconf manual */ # ifdef TIME_WITH_SYS_TIME @@ -36,119 +34,149 @@ # include # endif # endif - -/* - * Handling timer events under cygwin32 is not done with signal/setitimer. - * Instead of the two steps of first registering a signal handler to handle - * \tr{SIGVTALRM} and then start generating them via @setitimer()@, we use - * the Multimedia API (MM) and its @timeSetEvent@. (Internally, the MM API - * creates a separate thread that will notify the main thread of timer - * expiry). -- SOF 7/96 + +#ifdef HAVE_SIGNAL_H +# include +#endif + +/* Major bogosity: + * + * In the threaded RTS, we can't set the virtual timer because the + * thread which has the virtual timer might be sitting waiting for a + * capability, and the virtual timer only ticks in CPU time. * - * 11/98: if the cygwin DLL supports setitimer(), then use it instead. + * So, possible solutions: + * + * (1) tick in realtime. Not very good, because this ticker is used for + * profiling, and this will give us unreliable time profiling + * results. Furthermore, this requires picking a single OS thread + * to be the timekeeper, which is a bad idea because the thread in + * question might just be making a temporary call into Haskell land. + * + * (2) save/restore the virtual timer around excursions into STG land. + * Sounds great, but I tried it and the resolution of the virtual timer + * isn't good enough (on Linux) - most of our excursions fall + * within the timer's resolution and we never make any progress. + * + * (3) have a virtual timer in every OS thread. Might be reasonable, + * because most of the time there is only ever one of these + * threads running, so it approximates a single virtual timer. + * But still quite bogus (and I got crashes when I tried this). + * + * For now, we're using (1), but this needs a better solution. --SDM */ +#ifdef RTS_SUPPORTS_THREADS +#define ITIMER_FLAVOUR ITIMER_REAL +#define ITIMER_SIGNAL SIGALRM +#else +#define ITIMER_FLAVOUR ITIMER_VIRTUAL +#define ITIMER_SIGNAL SIGVTALRM +#endif + +static +int +install_vtalrm_handler(TickProc handle_tick) +{ + struct sigaction action; -#if defined(cygwin32_TARGET_OS) && !defined(HAVE_SETITIMER) + action.sa_handler = handle_tick; -#include /* OK, bring it all in... */ + sigemptyset(&action.sa_mask); + action.sa_flags = 0; -/* - vtalrm_handler is assigned and set up in - main/Signals.lc. - - vtalrm_id (defined in main/Signals.lc) holds - the system id for the current timer (used to - later block/kill the timer) -*/ -extern nat vtalrm_id; -extern TIMECALLBACK *vtalrm_cback; - -nat -initialize_virtual_timer(nat ms) -{ - /* VTALRM is currently not supported by cygwin32, - so we use the Timer support provided by the - MultiMedia API that is part of Win32. The - parameters to timeSetEvent may require some tweaking. - */ - unsigned int delay,vtalrm_id; - - delay = timeBeginPeriod(1); - if (delay == TIMERR_NOCANDO) { /* error of some sort. */ - return delay; - } - vtalrm_id = - timeSetEvent(ms, /* event every `delay' milliseconds. */ - 1, /* precision is within 5 millisecs. */ - (LPTIMECALLBACK)vtalrm_cback, - 0, - TIME_PERIODIC); - return 0; + return sigaction(ITIMER_SIGNAL, &action, NULL); } - -#else -nat -initialize_virtual_timer(nat ms) +int +startTicker(nat ms, TickProc handle_tick) { # ifndef HAVE_SETITIMER - fprintf(stderr, "No virtual timer on this system\n"); + /* debugBelch("No virtual timer on this system\n"); */ return -1; # else struct itimerval it; + install_vtalrm_handler(handle_tick); + + timestamp = getourtimeofday(); + it.it_value.tv_sec = ms / 1000; it.it_value.tv_usec = 1000 * (ms - (1000 * it.it_value.tv_sec)); it.it_interval = it.it_value; - return (setitimer(ITIMER_VIRTUAL, &it, NULL)); + return (setitimer(ITIMER_FLAVOUR, &it, NULL)); # endif } -#endif /* !cygwin32_TARGET_OS */ +int +stopTicker() +{ +# ifndef HAVE_SETITIMER + /* debugBelch("No virtual timer on this system\n"); */ + return -1; +# else + struct itimerval it; + + it.it_value.tv_sec = 0; + it.it_value.tv_usec = 0; + it.it_interval = it.it_value; + return (setitimer(ITIMER_FLAVOUR, &it, NULL)); +# endif +} # if 0 /* This is a potential POSIX version */ -nat -initialize_virtual_timer(nat ms) +int +startTicker(nat ms) { struct sigevent se; struct itimerspec it; timer_t tid; + timestamp = getourtimeofday(); + se.sigev_notify = SIGEV_SIGNAL; - se.sigev_signo = SIGVTALRM; - se.sigev_value.sival_int = SIGVTALRM; + se.sigev_signo = ITIMER_SIGNAL; + se.sigev_value.sival_int = ITIMER_SIGNAL; if (timer_create(CLOCK_VIRTUAL, &se, &tid)) { - fprintf(stderr, "Can't create virtual timer.\n"); - EXIT(EXIT_FAILURE); + barf("can't create virtual timer"); } it.it_value.tv_sec = ms / 1000; it.it_value.tv_nsec = 1000000 * (ms - 1000 * it.it_value.tv_sec); it.it_interval = it.it_value; - timer_settime(tid, TIMER_RELTIME, &it, NULL); + return timer_settime(tid, TIMER_RELTIME, &it, NULL); } -# endif int -install_vtalrm_handler(void (*handler)(int)) +stopTicker() { - struct sigaction action; + struct sigevent se; + struct itimerspec it; + timer_t tid; - action.sa_handler = handler; + timestamp = getourtimeofday(); - sigemptyset(&action.sa_mask); - action.sa_flags = 0; - - return sigaction(SIGVTALRM, &action, NULL); + se.sigev_notify = SIGEV_SIGNAL; + se.sigev_signo = ITIMER_SIGNAL; + se.sigev_value.sival_int = ITIMER_SIGNAL; + if (timer_create(CLOCK_VIRTUAL, &se, &tid)) { + barf("can't create virtual timer"); + } + it.it_value.tv_sec = 0; + it.it_value.tv_nsec = 0; + it.it_interval = it.it_value; + return timer_settime(tid, TIMER_RELTIME, &it, NULL); } +# endif +#if 0 +/* Currently unused */ void block_vtalrm_signal(void) { sigset_t signals; sigemptyset(&signals); - sigaddset(&signals, SIGVTALRM); + sigaddset(&signals, ITIMER_SIGNAL); (void) sigprocmask(SIG_BLOCK, &signals, NULL); } @@ -159,7 +187,22 @@ unblock_vtalrm_signal(void) sigset_t signals; sigemptyset(&signals); - sigaddset(&signals, SIGVTALRM); + sigaddset(&signals, ITIMER_SIGNAL); (void) sigprocmask(SIG_UNBLOCK, &signals, NULL); } +#endif + +/* gettimeofday() takes around 1us on our 500MHz PIII. Since we're + * only calling it 50 times/s, it shouldn't have any great impact. + */ +nat +getourtimeofday(void) +{ + struct timeval tv; + gettimeofday(&tv, (struct timezone *) NULL); + // cast to nat because nat may be 64 bit when int is only 32 bit + return ((nat)tv.tv_sec * TICK_FREQUENCY + + (nat)tv.tv_usec * TICK_FREQUENCY / 1000000); +} +