From 454f2ef1c95a9d543fc5a66eca4f286a3144b7ce Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn-Egil=20Dahlberg?= Date: Mon, 20 Dec 2010 11:56:50 +0100 Subject: Remove timer-thread implementation --- erts/emulator/sys/unix/erl_unix_sys.h | 7 -- erts/emulator/sys/unix/sys.c | 223 ---------------------------------- 2 files changed, 230 deletions(-) (limited to 'erts/emulator/sys') diff --git a/erts/emulator/sys/unix/erl_unix_sys.h b/erts/emulator/sys/unix/erl_unix_sys.h index 2d5ef882f6..824678a0bb 100644 --- a/erts/emulator/sys/unix/erl_unix_sys.h +++ b/erts/emulator/sys/unix/erl_unix_sys.h @@ -329,11 +329,4 @@ extern int exit_async(void); #define ERTS_EXIT_AFTER_DUMP _exit -#ifdef ERTS_TIMER_THREAD -struct erts_iwait; /* opaque for clients */ -extern struct erts_iwait *erts_iwait_init(void); -extern void erts_iwait_wait(struct erts_iwait *iwait, struct timeval *delay); -extern void erts_iwait_interrupt(struct erts_iwait *iwait); -#endif /* ERTS_TIMER_THREAD */ - #endif /* #ifndef _ERL_UNIX_SYS_H */ diff --git a/erts/emulator/sys/unix/sys.c b/erts/emulator/sys/unix/sys.c index d021baa6bf..bfc04faa45 100644 --- a/erts/emulator/sys/unix/sys.c +++ b/erts/emulator/sys/unix/sys.c @@ -3109,226 +3109,3 @@ erl_sys_args(int* argc, char** argv) } *argc = j; } - -#ifdef ERTS_TIMER_THREAD - -/* - * Interruptible-wait facility: low-level synchronisation state - * and methods that are implementation dependent. - * - * Constraint: Every implementation must define 'struct erts_iwait' - * with a field 'erts_smp_atomic_t state;'. - */ - -/* values for struct erts_iwait's state field */ -#define IWAIT_WAITING 0 -#define IWAIT_AWAKE 1 -#define IWAIT_INTERRUPT 2 - -#if 0 /* XXX: needs feature test in erts/configure.in */ - -/* - * This is an implementation of the interruptible wait facility on - * top of Linux-specific futexes. - */ -#include -#define FUTEX_WAIT 0 -#define FUTEX_WAKE 1 -static int sys_futex(void *futex, int op, int val, const struct timespec *timeout) -{ - return syscall(__NR_futex, futex, op, val, timeout); -} - -struct erts_iwait { - erts_smp_atomic_t state; /* &state.counter is our futex */ -}; - -static void iwait_lowlevel_init(struct erts_iwait *iwait) { /* empty */ } - -static void iwait_lowlevel_wait(struct erts_iwait *iwait, struct timeval *delay) -{ - struct timespec timeout; - int res; - - timeout.tv_sec = delay->tv_sec; - timeout.tv_nsec = delay->tv_usec * 1000; - res = sys_futex((void*)&iwait->state.counter, FUTEX_WAIT, IWAIT_WAITING, &timeout); - if (res < 0 && errno != ETIMEDOUT && errno != EWOULDBLOCK && errno != EINTR) - perror("FUTEX_WAIT"); -} - -static void iwait_lowlevel_interrupt(struct erts_iwait *iwait) -{ - int res = sys_futex((void*)&iwait->state.counter, FUTEX_WAKE, 1, NULL); - if (res < 0) - perror("FUTEX_WAKE"); -} - -#else /* using poll() or select() */ - -/* - * This is an implementation of the interruptible wait facility on - * top of pipe(), poll() or select(), read(), and write(). - */ -struct erts_iwait { - erts_smp_atomic_t state; - int read_fd; /* wait polls and reads this fd */ - int write_fd; /* interrupt writes this fd */ -}; - -static void iwait_lowlevel_init(struct erts_iwait *iwait) -{ - int fds[2]; - - if (pipe(fds) < 0) { - perror("pipe()"); - exit(1); - } - iwait->read_fd = fds[0]; - iwait->write_fd = fds[1]; -} - -#if defined(ERTS_USE_POLL) - -#include -#define PERROR_POLL "poll()" - -static int iwait_lowlevel_poll(int read_fd, struct timeval *delay) -{ - struct pollfd pollfd; - int timeout; - - pollfd.fd = read_fd; - pollfd.events = POLLIN; - pollfd.revents = 0; - timeout = delay->tv_sec * 1000 + delay->tv_usec / 1000; - return poll(&pollfd, 1, timeout); -} - -#else /* !ERTS_USE_POLL */ - -#include -#define PERROR_POLL "select()" - -static int iwait_lowlevel_poll(int read_fd, struct timeval *delay) -{ - fd_set readfds; - - FD_ZERO(&readfds); - FD_SET(read_fd, &readfds); - return select(read_fd + 1, &readfds, NULL, NULL, delay); -} - -#endif /* !ERTS_USE_POLL */ - -static void iwait_lowlevel_wait(struct erts_iwait *iwait, struct timeval *delay) -{ - int res; - char buf[64]; - - res = iwait_lowlevel_poll(iwait->read_fd, delay); - if (res > 0) - (void)read(iwait->read_fd, buf, sizeof buf); - else if (res < 0 && errno != EINTR) - perror(PERROR_POLL); -} - -static void iwait_lowlevel_interrupt(struct erts_iwait *iwait) -{ - int res = write(iwait->write_fd, "!", 1); - if (res < 0) - perror("write()"); -} - -#endif /* using poll() or select() */ - -#if 0 /* not using poll() or select() */ -/* - * This is an implementation of the interruptible wait facility on - * top of pthread_cond_timedwait(). This has two problems: - * 1. pthread_cond_timedwait() requires an absolute time point, - * so the relative delay must be converted to absolute time. - * Worse, this breaks if the machine's time is adjusted while - * we're preparing to wait. - * 2. Each cond operation requires additional mutex lock/unlock operations. - * - * Problem 2 is probably not too bad on Linux (they'll just become - * relatively cheap futex operations), but problem 1 is the real killer. - * Only use this implementation if no better alternatives are available! - */ -struct erts_iwait { - erts_smp_atomic_t state; - pthread_cond_t cond; - pthread_mutex_t mutex; -}; - -static void iwait_lowlevel_init(struct erts_iwait *iwait) -{ - iwait->cond = (pthread_cond_t) PTHREAD_COND_INITIALIZER; - iwait->mutex = (pthread_mutex_t) PTHREAD_MUTEX_INITIALIZER; -} - -static void iwait_lowlevel_wait(struct erts_iwait *iwait, struct timeval *delay) -{ - struct timeval tmp; - struct timespec timeout; - - /* Due to pthread_cond_timedwait()'s use of absolute - time, this must be the real gettimeofday(), _not_ - the "smoothed" one beam/erl_time_sup.c implements. */ - gettimeofday(&tmp, NULL); - - tmp.tv_sec += delay->tv_sec; - tmp.tv_usec += delay->tv_usec; - if (tmp.tv_usec >= 1000*1000) { - tmp.tv_usec -= 1000*1000; - tmp.tv_sec += 1; - } - timeout.tv_sec = tmp.tv_sec; - timeout.tv_nsec = tmp.tv_usec * 1000; - pthread_mutex_lock(&iwait->mutex); - pthread_cond_timedwait(&iwait->cond, &iwait->mutex, &timeout); - pthread_mutex_unlock(&iwait->mutex); -} - -static void iwait_lowlevel_interrupt(struct erts_iwait *iwait) -{ - pthread_mutex_lock(&iwait->mutex); - pthread_cond_signal(&iwait->cond); - pthread_mutex_unlock(&iwait->mutex); -} - -#endif /* not using POLL */ - -/* - * Interruptible-wait facility. This is just a wrapper around the - * low-level synchronisation code, where we maintain our logical - * state in order to suppress some state transitions. - */ - -struct erts_iwait *erts_iwait_init(void) -{ - struct erts_iwait *iwait = malloc(sizeof *iwait); - if (!iwait) { - perror("malloc"); - exit(1); - } - iwait_lowlevel_init(iwait); - erts_smp_atomic_init(&iwait->state, IWAIT_AWAKE); - return iwait; -} - -void erts_iwait_wait(struct erts_iwait *iwait, struct timeval *delay) -{ - if (erts_smp_atomic_xchg(&iwait->state, IWAIT_WAITING) != IWAIT_INTERRUPT) - iwait_lowlevel_wait(iwait, delay); - erts_smp_atomic_set(&iwait->state, IWAIT_AWAKE); -} - -void erts_iwait_interrupt(struct erts_iwait *iwait) -{ - if (erts_smp_atomic_xchg(&iwait->state, IWAIT_INTERRUPT) == IWAIT_WAITING) - iwait_lowlevel_interrupt(iwait); -} - -#endif /* ERTS_TIMER_THREAD */ -- cgit v1.2.3