X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=sched.c;h=cdc5b65828788bd0dc359c372a928f8d4cecb3db;hp=4df32fa1b16aa388eb46683bdd307c2a127c070c;hb=6b935f552ebfe3a0a83ec9367deb2f42c1aff252;hpb=4fc040bcb794981726c20759ce6ad4aadebc3ff4 diff --git a/sched.c b/sched.c index 4df32fa1..cdc5b658 100644 --- a/sched.c +++ b/sched.c @@ -1,11 +1,12 @@ /* - * Copyright (C) 2006-2008 Andre Noll + * Copyright (C) 2006-2010 Andre Noll * * Licensed under the GPL v2. For licencing details see COPYING. */ /** \file sched.c Paraslash's scheduling functions. */ +#include #include /* readdir() */ #include #include @@ -16,6 +17,7 @@ #include "list.h" #include "sched.h" #include "string.h" +#include "time.h" #include "error.h" static struct list_head pre_select_list, post_select_list; @@ -24,7 +26,7 @@ static int initialized; static struct timeval now_struct; struct timeval *now = &now_struct; -/** +/* * Remove a task from the scheduler. * * \param t The task to remove. @@ -43,14 +45,14 @@ static void unregister_task(struct task *t) if (t->post_select) list_del(&t->post_select_node); t->error = -E_TASK_UNREGISTERED; -}; +} static void sched_preselect(struct sched *s) { struct task *t, *tmp; list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node) { - if (t->error >= 0) + if (t->error >= 0 && t->pre_select) t->pre_select(s, t); // PARA_INFO_LOG("%s \n", t->status); if (t->error >= 0) @@ -67,13 +69,33 @@ static void sched_preselect(struct sched *s) } } +//#define SCHED_DEBUG 1 +static inline void call_post_select(struct sched *s, struct task *t) +{ +#ifndef SCHED_DEBUG + t->post_select(s, t); +#else + struct timeval t1, t2, diff; + unsigned long pst; + + gettimeofday(&t1, NULL); + t->post_select(s, t); + gettimeofday(&t2, NULL); + tv_diff(&t1, &t2, &diff); + pst = tv2ms(&diff); + if (pst > 50) + PARA_WARNING_LOG("%s: post_select time: %lums\n", + t->status, pst); +#endif +} + static void sched_post_select(struct sched *s) { struct task *t, *tmp; list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) { if (t->error >= 0) - t->post_select(s, t); + call_post_select(s, t); // PARA_INFO_LOG("%s: %d\n", t->status, t->ret); if (t->error >= 0) continue; @@ -107,18 +129,28 @@ int schedule(struct sched *s) return -E_NOT_INITIALIZED; if (!s->select_function) s->select_function = para_select; - gettimeofday(now, NULL); again: FD_ZERO(&s->rfds); FD_ZERO(&s->wfds); s->timeout = s->default_timeout; s->max_fileno = -1; + gettimeofday(now, NULL); sched_preselect(s); if (list_empty(&pre_select_list) && list_empty(&post_select_list)) return 0; ret = s->select_function(s->max_fileno + 1, &s->rfds, &s->wfds, &s->timeout); if (ret < 0) return ret; + if (ret == 0) { + /* + * APUE: Be careful not to check the descriptor sets on return + * unless the return value is greater than zero. The return + * state of the descriptor sets is implementation dependent if + * either a signal is caught or the timer expires. + */ + FD_ZERO(&s->rfds); + FD_ZERO(&s->wfds); + } gettimeofday(now, NULL); sched_post_select(s); if (list_empty(&pre_select_list) && list_empty(&post_select_list)) @@ -126,7 +158,7 @@ again: goto again; } -/** +/* * Initialize the paraslash scheduler. */ static void init_sched(void) @@ -135,7 +167,7 @@ static void init_sched(void) INIT_LIST_HEAD(&pre_select_list); INIT_LIST_HEAD(&post_select_list); initialized = 1; -}; +} /** * Add a task to the scheduler. @@ -157,7 +189,7 @@ void register_task(struct task *t) list_add_tail(&t->pre_select_node, &pre_select_list); } if (t->post_select) { - PARA_DEBUG_LOG("post_select: %p\n", &t->pre_select); + PARA_DEBUG_LOG("post_select: %p\n", &t->post_select); list_add_tail(&t->post_select_node, &post_select_list); } } @@ -179,7 +211,7 @@ void sched_shutdown(void) list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) unregister_task(t); initialized = 0; -}; +} /** * Get the list of all registered tasks. @@ -188,7 +220,7 @@ void sched_shutdown(void) * * Each entry of the list contains an identifier which is simply a hex number * that may be used in \a kill_task() to terminate the task. - * The result ist dynamically allocated and must be freed by the caller. + * The result is dynamically allocated and must be freed by the caller. */ char *get_task_list(void) { @@ -249,3 +281,88 @@ int kill_task(char *id) } return -E_NO_SUCH_TASK; } + +/** + * Set the select timeout to the minimal possible value. + * + * \param s Pointer to the scheduler struct. + * + * This causes the next select() call to return immediately. + */ +void sched_min_delay(struct sched *s) +{ + s->timeout.tv_sec = 0; + s->timeout.tv_usec = 1; +} + +/** + * Impose an upper bound for the timeout of the next select() call. + * + * \param timeout Maximal allowed timeout. + * \param s Pointer to the scheduler struct. + * + * If the current scheduler timeout is already smaller than \a timeout, this + * function does nothing. Otherwise the timeout for the next select() call is + * set to the given value. + * + * \sa sched_request_timeout_ms(). + */ +void sched_request_timeout(struct timeval *timeout, struct sched *s) +{ + if (tv_diff(&s->timeout, timeout, NULL) > 0) + s->timeout = *timeout; +} + +/** + * Force the next select() call to return before the given amount of milliseconds. + * + * \param ms The maximal allowed timeout in milliseconds. + * \param s Pointer to the scheduler struct. + * + * Like sched_request_timeout() this imposes an upper bound on the timeout + * value for the next select() call. + */ +void sched_request_timeout_ms(long unsigned ms, struct sched *s) +{ + struct timeval tv; + ms2tv(ms, &tv); + sched_request_timeout(&tv, s); +} + +/** + * Force the next select() call to return before the given future time. + * + * \param barrier Absolute time before select() should return. + * \param s Pointer to the scheduler struct. + * + * If \a barrier is in the past, this function does nothing. + * + * \sa sched_request_barrier_or_min_delay(). + */ +void sched_request_barrier(struct timeval *barrier, struct sched *s) +{ + struct timeval diff; + + if (tv_diff(now, barrier, &diff) > 0) + return; + sched_request_timeout(&diff, s); +} + +/** + * Force the next select() call to return before the given time. + * + * \param barrier Absolute time before select() should return. + * \param s Pointer to the scheduler struct. + * + * If \a barrier is in the past, this function requests a minimal timeout. + * + * \sa sched_min_delay(), sched_request_barrier(). + */ +void sched_request_barrier_or_min_delay(struct timeval *barrier, struct sched *s) +{ + struct timeval diff; + + if (tv_diff(now, barrier, &diff) > 0) + return sched_min_delay(s); + sched_request_timeout(&diff, s); +}