+++ /dev/null
-/* -----------------------------------------------------------------------------
- *
- * (c) The GHC Team, 1995-1999
- *
- * Interval timer for profiling and pre-emptive scheduling.
- *
- * ---------------------------------------------------------------------------*/
-
-/*
- * The interval timer is used for profiling and for context switching in the
- * threaded build. Though POSIX 1003.1b includes a standard interface for
- * such things, no one really seems to be implementing them yet. Even
- * Solaris 2.3 only seems to provide support for @CLOCK_REAL@, whereas we're
- * keen on getting access to @CLOCK_VIRTUAL@.
- *
- * Hence, we use the old-fashioned @setitimer@ that just about everyone seems
- * to support. So much for standards.
- */
-#include "Rts.h"
-#include "RtsFlags.h"
-#include "Timer.h"
-#include "Ticker.h"
-#include "posix/Itimer.h"
-#include "Proftimer.h"
-#include "Schedule.h"
-#include "posix/Select.h"
-
-/* As recommended in the autoconf manual */
-# ifdef TIME_WITH_SYS_TIME
-# include <sys/time.h>
-# include <time.h>
-# else
-# ifdef HAVE_SYS_TIME_H
-# include <sys/time.h>
-# else
-# include <time.h>
-# endif
-# endif
-
-#ifdef HAVE_SIGNAL_H
-# include <signal.h>
-#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.
- *
- * 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 THREADED_RTS
-#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;
-
- action.sa_handler = handle_tick;
-
- sigemptyset(&action.sa_mask);
-
-#ifdef SA_RESTART
- // specify SA_RESTART. One consequence if we don't do this is
- // that readline gets confused by the -threaded RTS. It seems
- // that if a SIGALRM handler is installed without SA_RESTART,
- // readline installs its own SIGALRM signal handler (see
- // readline's signals.c), and this somehow causes readline to go
- // wrong when the input exceeds a single line (try it).
- action.sa_flags = SA_RESTART;
-#else
- action.sa_flags = 0;
-#endif
-
- return sigaction(ITIMER_SIGNAL, &action, NULL);
-}
-
-int
-startTicker(nat ms, TickProc handle_tick)
-{
-# ifndef HAVE_SETITIMER
- /* debugBelch("No virtual timer on this system\n"); */
- return -1;
-# else
- struct itimerval it;
-
- install_vtalrm_handler(handle_tick);
-
-#if !defined(THREADED_RTS)
- timestamp = getourtimeofday();
-#endif
-
- 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_FLAVOUR, &it, NULL));
-# endif
-}
-
-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 */
-int
-startTicker(nat ms)
-{
- struct sigevent se;
- struct itimerspec it;
- timer_t tid;
-
-#if !defined(THREADED_RTS)
- timestamp = getourtimeofday();
-#endif
-
- 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 = ms / 1000;
- it.it_value.tv_nsec = 1000000 * (ms - 1000 * it.it_value.tv_sec);
- it.it_interval = it.it_value;
- return timer_settime(tid, TIMER_RELTIME, &it, NULL);
-}
-
-int
-stopTicker()
-{
- struct sigevent se;
- struct itimerspec it;
- timer_t tid;
-
-#if !defined(THREADED_RTS)
- timestamp = getourtimeofday();
-#endif
-
- 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, ITIMER_SIGNAL);
-
- (void) sigprocmask(SIG_BLOCK, &signals, NULL);
-}
-
-void
-unblock_vtalrm_signal(void)
-{
- sigset_t signals;
-
- sigemptyset(&signals);
- 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.
- */
-lnat
-getourtimeofday(void)
-{
- struct timeval tv;
- gettimeofday(&tv, (struct timezone *) NULL);
- // cast to lnat because nat may be 64 bit when int is only 32 bit
- return ((lnat)tv.tv_sec * TICK_FREQUENCY +
- (lnat)tv.tv_usec * TICK_FREQUENCY / 1000000);
-}
projects / ghc-hetmet.git / blobdiff