Index: linux-2.6.8-rc2-bk7/fs/proc/array.c =================================================================== --- linux-2.6.8-rc2-bk7.orig/fs/proc/array.c 2004-06-16 17:35:43.000000000 +1000 +++ linux-2.6.8-rc2-bk7/fs/proc/array.c 2004-07-29 09:52:00.966205999 +1000 @@ -155,7 +155,7 @@ read_lock(&tasklist_lock); buffer += sprintf(buffer, "State:\t%s\n" - "SleepAVG:\t%lu%%\n" + "Burst:\t%d\n" "Tgid:\t%d\n" "Pid:\t%d\n" "PPid:\t%d\n" @@ -163,7 +163,7 @@ "Uid:\t%d\t%d\t%d\t%d\n" "Gid:\t%d\t%d\t%d\t%d\n", get_task_state(p), - (p->sleep_avg/1024)*100/(1020000000/1024), + p->burst, p->tgid, p->pid, p->pid ? p->real_parent->pid : 0, p->pid && p->ptrace ? p->parent->pid : 0, Index: linux-2.6.8-rc2-bk7/include/linux/sched.h =================================================================== --- linux-2.6.8-rc2-bk7.orig/include/linux/sched.h 2004-07-29 09:48:35.951393507 +1000 +++ linux-2.6.8-rc2-bk7/include/linux/sched.h 2004-07-29 09:52:00.967205842 +1000 @@ -164,6 +164,7 @@ void io_schedule(void); long io_schedule_timeout(long timeout); +extern int sched_interactive, sched_compute; extern void cpu_init (void); extern void trap_init(void); @@ -323,7 +324,6 @@ extern struct user_struct root_user; #define INIT_USER (&root_user) -typedef struct prio_array prio_array_t; struct backing_dev_info; struct reclaim_state; @@ -398,16 +398,13 @@ int prio, static_prio; struct list_head run_list; - prio_array_t *array; - - unsigned long sleep_avg; - long interactive_credit; unsigned long long timestamp; - int activated; + unsigned long runtime, totalrun; + unsigned int burst; unsigned long policy; cpumask_t cpus_allowed; - unsigned int time_slice, first_time_slice; + unsigned int slice, time_slice; struct list_head tasks; struct list_head ptrace_children; @@ -555,6 +552,9 @@ #define PF_SWAPOFF 0x00080000 /* I am in swapoff */ #define PF_LESS_THROTTLE 0x00100000 /* Throttle me less: I clean memory */ #define PF_SYNCWRITE 0x00200000 /* I am doing a sync write */ +#define PF_FORKED 0x00400000 /* I have just forked */ +#define PF_YIELDED 0x00800000 /* I have just yielded */ +#define PF_UISLEEP 0x01000000 /* Uninterruptible sleep */ #ifdef CONFIG_SMP #define SCHED_LOAD_SCALE 128UL /* increase resolution of load */ @@ -753,7 +753,6 @@ } #endif extern void FASTCALL(sched_fork(task_t * p)); -extern void FASTCALL(sched_exit(task_t * p)); extern int in_group_p(gid_t); extern int in_egroup_p(gid_t); Index: linux-2.6.8-rc2-bk7/include/linux/sysctl.h =================================================================== --- linux-2.6.8-rc2-bk7.orig/include/linux/sysctl.h 2004-07-29 09:48:35.960392095 +1000 +++ linux-2.6.8-rc2-bk7/include/linux/sysctl.h 2004-07-29 09:52:00.968205685 +1000 @@ -133,6 +133,8 @@ KERN_NGROUPS_MAX=63, /* int: NGROUPS_MAX */ KERN_SPARC_SCONS_PWROFF=64, /* int: serial console power-off halt */ KERN_HZ_TIMER=65, /* int: hz timer on or off */ + KERN_INTERACTIVE=66, /* interactive tasks can have cpu bursts */ + KERN_COMPUTE=67, /* adjust timeslices for a compute server */ }; Index: linux-2.6.8-rc2-bk7/kernel/exit.c =================================================================== --- linux-2.6.8-rc2-bk7.orig/kernel/exit.c 2004-07-29 09:48:35.997386290 +1000 +++ linux-2.6.8-rc2-bk7/kernel/exit.c 2004-07-29 09:52:00.969205528 +1000 @@ -96,7 +96,6 @@ p->parent->cmaj_flt += p->maj_flt + p->cmaj_flt; p->parent->cnvcsw += p->nvcsw + p->cnvcsw; p->parent->cnivcsw += p->nivcsw + p->cnivcsw; - sched_exit(p); write_unlock_irq(&tasklist_lock); spin_unlock(&p->proc_lock); proc_pid_flush(proc_dentry); Index: linux-2.6.8-rc2-bk7/kernel/sched.c =================================================================== --- linux-2.6.8-rc2-bk7.orig/kernel/sched.c 2004-07-29 09:48:36.010384251 +1000 +++ linux-2.6.8-rc2-bk7/kernel/sched.c 2004-07-29 09:53:28.048522643 +1000 @@ -16,6 +16,8 @@ * by Davide Libenzi, preemptible kernel bits by Robert Love. * 2003-09-03 Interactivity tuning by Con Kolivas. * 2004-04-02 Scheduler domains code by Nick Piggin + * 2004-07-07 New staircase scheduling policy by Con Kolivas with help + * from William Lee Irwin III, Zwane Mwaikambo & Peter Williams. */ #include @@ -44,12 +46,6 @@ #include -#ifdef CONFIG_NUMA -#define cpu_to_node_mask(cpu) node_to_cpumask(cpu_to_node(cpu)) -#else -#define cpu_to_node_mask(cpu) (cpu_online_map) -#endif - /* * Convert user-nice values [ -20 ... 0 ... 19 ] * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ], @@ -67,118 +63,20 @@ #define USER_PRIO(p) ((p)-MAX_RT_PRIO) #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio) #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO)) -#define AVG_TIMESLICE (MIN_TIMESLICE + ((MAX_TIMESLICE - MIN_TIMESLICE) *\ - (MAX_PRIO-1-NICE_TO_PRIO(0))/(MAX_USER_PRIO - 1))) /* * Some helpers for converting nanosecond timing to jiffy resolution */ #define NS_TO_JIFFIES(TIME) ((TIME) / (1000000000 / HZ)) -#define JIFFIES_TO_NS(TIME) ((TIME) * (1000000000 / HZ)) - -/* - * These are the 'tuning knobs' of the scheduler: - * - * Minimum timeslice is 10 msecs, default timeslice is 100 msecs, - * maximum timeslice is 200 msecs. Timeslices get refilled after - * they expire. - */ -#define MIN_TIMESLICE ( 10 * HZ / 1000) -#define MAX_TIMESLICE (200 * HZ / 1000) -#define ON_RUNQUEUE_WEIGHT 30 -#define CHILD_PENALTY 95 -#define PARENT_PENALTY 100 -#define EXIT_WEIGHT 3 -#define PRIO_BONUS_RATIO 25 -#define MAX_BONUS (MAX_USER_PRIO * PRIO_BONUS_RATIO / 100) -#define INTERACTIVE_DELTA 2 -#define MAX_SLEEP_AVG (AVG_TIMESLICE * MAX_BONUS) -#define STARVATION_LIMIT (MAX_SLEEP_AVG) -#define NS_MAX_SLEEP_AVG (JIFFIES_TO_NS(MAX_SLEEP_AVG)) -#define CREDIT_LIMIT 100 - -/* - * If a task is 'interactive' then we reinsert it in the active - * array after it has expired its current timeslice. (it will not - * continue to run immediately, it will still roundrobin with - * other interactive tasks.) - * - * This part scales the interactivity limit depending on niceness. - * - * We scale it linearly, offset by the INTERACTIVE_DELTA delta. - * Here are a few examples of different nice levels: - * - * TASK_INTERACTIVE(-20): [1,1,1,1,1,1,1,1,1,0,0] - * TASK_INTERACTIVE(-10): [1,1,1,1,1,1,1,0,0,0,0] - * TASK_INTERACTIVE( 0): [1,1,1,1,0,0,0,0,0,0,0] - * TASK_INTERACTIVE( 10): [1,1,0,0,0,0,0,0,0,0,0] - * TASK_INTERACTIVE( 19): [0,0,0,0,0,0,0,0,0,0,0] - * - * (the X axis represents the possible -5 ... 0 ... +5 dynamic - * priority range a task can explore, a value of '1' means the - * task is rated interactive.) - * - * Ie. nice +19 tasks can never get 'interactive' enough to be - * reinserted into the active array. And only heavily CPU-hog nice -20 - * tasks will be expired. Default nice 0 tasks are somewhere between, - * it takes some effort for them to get interactive, but it's not - * too hard. - */ - -#define CURRENT_BONUS(p) \ - (NS_TO_JIFFIES((p)->sleep_avg) * MAX_BONUS / \ - MAX_SLEEP_AVG) - -#ifdef CONFIG_SMP -#define TIMESLICE_GRANULARITY(p) (MIN_TIMESLICE * \ - (1 << (((MAX_BONUS - CURRENT_BONUS(p)) ? : 1) - 1)) * \ - num_online_cpus()) -#else -#define TIMESLICE_GRANULARITY(p) (MIN_TIMESLICE * \ - (1 << (((MAX_BONUS - CURRENT_BONUS(p)) ? : 1) - 1))) -#endif - -#define SCALE(v1,v1_max,v2_max) \ - (v1) * (v2_max) / (v1_max) - -#define DELTA(p) \ - (SCALE(TASK_NICE(p), 40, MAX_BONUS) + INTERACTIVE_DELTA) - -#define TASK_INTERACTIVE(p) \ - ((p)->prio <= (p)->static_prio - DELTA(p)) -#define INTERACTIVE_SLEEP(p) \ - (JIFFIES_TO_NS(MAX_SLEEP_AVG * \ - (MAX_BONUS / 2 + DELTA((p)) + 1) / MAX_BONUS - 1)) - -#define HIGH_CREDIT(p) \ - ((p)->interactive_credit > CREDIT_LIMIT) - -#define LOW_CREDIT(p) \ - ((p)->interactive_credit < -CREDIT_LIMIT) - -#define TASK_PREEMPTS_CURR(p, rq) \ - ((p)->prio < (rq)->curr->prio) - -/* - * BASE_TIMESLICE scales user-nice values [ -20 ... 19 ] - * to time slice values. - * - * The higher a thread's priority, the bigger timeslices - * it gets during one round of execution. But even the lowest - * priority thread gets MIN_TIMESLICE worth of execution time. - * - * task_timeslice() is the interface that is used by the scheduler. +int sched_compute = 0; +/* + *This is the time all tasks within the same priority round robin. + *compute setting is reserved for dedicated computational scheduling + *and has ten times larger intervals. */ - -#define BASE_TIMESLICE(p) (MIN_TIMESLICE + \ - ((MAX_TIMESLICE - MIN_TIMESLICE) * \ - (MAX_PRIO-1 - (p)->static_prio) / (MAX_USER_PRIO-1))) - -static unsigned int task_timeslice(task_t *p) -{ - return BASE_TIMESLICE(p); -} +#define _RR_INTERVAL ((10 * HZ / 1000) ? : 1) +#define RR_INTERVAL() (_RR_INTERVAL * (1 + 9 * sched_compute)) #define task_hot(p, now, sd) ((now) - (p)->timestamp < (sd)->cache_hot_time) @@ -186,16 +84,8 @@ * These are the runqueue data structures: */ -#define BITMAP_SIZE ((((MAX_PRIO+1+7)/8)+sizeof(long)-1)/sizeof(long)) - typedef struct runqueue runqueue_t; -struct prio_array { - unsigned int nr_active; - unsigned long bitmap[BITMAP_SIZE]; - struct list_head queue[MAX_PRIO]; -}; - /* * This is the main, per-CPU runqueue data structure. * @@ -215,12 +105,13 @@ unsigned long cpu_load; #endif unsigned long long nr_switches; - unsigned long expired_timestamp, nr_uninterruptible; + unsigned long nr_uninterruptible; unsigned long long timestamp_last_tick; + unsigned int cache_ticks, preempted; task_t *curr, *idle; struct mm_struct *prev_mm; - prio_array_t *active, *expired, arrays[2]; - int best_expired_prio; + unsigned long bitmap[BITS_TO_LONGS(MAX_PRIO+1)]; + struct list_head queue[MAX_PRIO + 1]; atomic_t nr_iowait; #ifdef CONFIG_SMP @@ -298,23 +189,25 @@ spin_unlock_irq(&rq->lock); } +static inline int task_queued(task_t *task) +{ + return !list_empty(&task->run_list); +} + /* - * Adding/removing a task to/from a priority array: + * Adding/removing a task to/from a runqueue: */ -static void dequeue_task(struct task_struct *p, prio_array_t *array) +static void dequeue_task(struct task_struct *p, runqueue_t *rq) { - array->nr_active--; - list_del(&p->run_list); - if (list_empty(array->queue + p->prio)) - __clear_bit(p->prio, array->bitmap); + list_del_init(&p->run_list); + if (list_empty(rq->queue + p->prio)) + __clear_bit(p->prio, rq->bitmap); } -static void enqueue_task(struct task_struct *p, prio_array_t *array) +static void enqueue_task(struct task_struct *p, runqueue_t *rq) { - list_add_tail(&p->run_list, array->queue + p->prio); - __set_bit(p->prio, array->bitmap); - array->nr_active++; - p->array = array; + list_add_tail(&p->run_list, rq->queue + p->prio); + __set_bit(p->prio, rq->bitmap); } /* @@ -322,43 +215,10 @@ * remote queue so we want these tasks to show up at the head of the * local queue: */ -static inline void enqueue_task_head(struct task_struct *p, prio_array_t *array) -{ - list_add(&p->run_list, array->queue + p->prio); - __set_bit(p->prio, array->bitmap); - array->nr_active++; - p->array = array; -} - -/* - * effective_prio - return the priority that is based on the static - * priority but is modified by bonuses/penalties. - * - * We scale the actual sleep average [0 .... MAX_SLEEP_AVG] - * into the -5 ... 0 ... +5 bonus/penalty range. - * - * We use 25% of the full 0...39 priority range so that: - * - * 1) nice +19 interactive tasks do not preempt nice 0 CPU hogs. - * 2) nice -20 CPU hogs do not get preempted by nice 0 tasks. - * - * Both properties are important to certain workloads. - */ -static int effective_prio(task_t *p) +static inline void enqueue_task_head(struct task_struct *p, runqueue_t *rq) { - int bonus, prio; - - if (rt_task(p)) - return p->prio; - - bonus = CURRENT_BONUS(p) - MAX_BONUS / 2; - - prio = p->static_prio - bonus; - if (prio < MAX_RT_PRIO) - prio = MAX_RT_PRIO; - if (prio > MAX_PRIO-1) - prio = MAX_PRIO-1; - return prio; + list_add(&p->run_list, rq->queue + p->prio); + __set_bit(p->prio, rq->bitmap); } /* @@ -366,7 +226,7 @@ */ static inline void __activate_task(task_t *p, runqueue_t *rq) { - enqueue_task(p, rq->active); + enqueue_task(p, rq); rq->nr_running++; } @@ -375,95 +235,121 @@ */ static inline void __activate_idle_task(task_t *p, runqueue_t *rq) { - enqueue_task_head(p, rq->active); + enqueue_task_head(p, rq); rq->nr_running++; } -static void recalc_task_prio(task_t *p, unsigned long long now) +/* + * burst - extra intervals an interactive task can run for at best priority + * instead of descending priorities. + */ +static unsigned int burst(task_t *p) { - unsigned long long __sleep_time = now - p->timestamp; - unsigned long sleep_time; + if (likely(!rt_task(p))) { + unsigned int task_user_prio = TASK_USER_PRIO(p); + return 39 - task_user_prio; + } else + return p->burst; +} - if (__sleep_time > NS_MAX_SLEEP_AVG) - sleep_time = NS_MAX_SLEEP_AVG; - else - sleep_time = (unsigned long)__sleep_time; +static void inc_burst(task_t *p) +{ + unsigned int best_burst; + best_burst = burst(p); + if (p->burst < best_burst) + p->burst++; +} - if (likely(sleep_time > 0)) { - /* - * User tasks that sleep a long time are categorised as - * idle and will get just interactive status to stay active & - * prevent them suddenly becoming cpu hogs and starving - * other processes. - */ - if (p->mm && p->activated != -1 && - sleep_time > INTERACTIVE_SLEEP(p)) { - p->sleep_avg = JIFFIES_TO_NS(MAX_SLEEP_AVG - - AVG_TIMESLICE); - if (!HIGH_CREDIT(p)) - p->interactive_credit++; - } else { - /* - * The lower the sleep avg a task has the more - * rapidly it will rise with sleep time. - */ - sleep_time *= (MAX_BONUS - CURRENT_BONUS(p)) ? : 1; +static void dec_burst(task_t *p) +{ + if (p->burst) + p->burst--; +} - /* - * Tasks with low interactive_credit are limited to - * one timeslice worth of sleep avg bonus. - */ - if (LOW_CREDIT(p) && - sleep_time > JIFFIES_TO_NS(task_timeslice(p))) - sleep_time = JIFFIES_TO_NS(task_timeslice(p)); +/* + * slice - the duration a task runs before getting requeued at it's best + * priority and has it's burst decremented. + */ +static unsigned int slice(task_t *p) +{ + unsigned int slice = RR_INTERVAL(); + if (likely(!rt_task(p))) + slice += burst(p) * RR_INTERVAL(); + return slice; +} - /* - * Non high_credit tasks waking from uninterruptible - * sleep are limited in their sleep_avg rise as they - * are likely to be cpu hogs waiting on I/O - */ - if (p->activated == -1 && !HIGH_CREDIT(p) && p->mm) { - if (p->sleep_avg >= INTERACTIVE_SLEEP(p)) - sleep_time = 0; - else if (p->sleep_avg + sleep_time >= - INTERACTIVE_SLEEP(p)) { - p->sleep_avg = INTERACTIVE_SLEEP(p); - sleep_time = 0; - } - } +/* + * sched_interactive - sysctl which allows interactive tasks to have bursts + */ +int sched_interactive = 1; - /* - * This code gives a bonus to interactive tasks. - * - * The boost works by updating the 'average sleep time' - * value here, based on ->timestamp. The more time a - * task spends sleeping, the higher the average gets - - * and the higher the priority boost gets as well. - */ - p->sleep_avg += sleep_time; +/* + * effective_prio - dynamic priority dependent on burst. + * The priority normally decreases by one each RR_INTERVAL. + * As the burst increases the priority stays at the top "stair" or + * priority for longer. + */ +static int effective_prio(task_t *p) +{ + int prio; + unsigned int full_slice, used_slice, first_slice; + unsigned int best_burst; + if (rt_task(p)) + return p->prio; - if (p->sleep_avg > NS_MAX_SLEEP_AVG) { - p->sleep_avg = NS_MAX_SLEEP_AVG; - if (!HIGH_CREDIT(p)) - p->interactive_credit++; + best_burst = burst(p); + full_slice = slice(p); + used_slice = full_slice - p->slice; + if (p->burst > best_burst) + p->burst = best_burst; + first_slice = RR_INTERVAL(); + if (sched_interactive && !sched_compute) + first_slice *= (p->burst + 1); + prio = MAX_PRIO - 1 - best_burst; + + if (used_slice < first_slice) + return prio; + prio += 1 + (used_slice - first_slice) / RR_INTERVAL(); + if (prio > MAX_PRIO - 1) + prio = MAX_PRIO - 1; + return prio; +} + +/* + * recalc_task_prio - this checks for tasks that run ultra short timeslices + * or have just forked a thread/process and make them continue their old + * slice instead of starting a new one at high priority. + */ +static void recalc_task_prio(task_t *p, unsigned long long now) +{ + unsigned long sleep_time = now - p->timestamp; + unsigned long ns_totalrun = p->totalrun + p->runtime; + unsigned long total_run = NS_TO_JIFFIES(ns_totalrun); + if (p->flags & PF_FORKED || ((!(NS_TO_JIFFIES(p->runtime)) || + !sched_interactive || sched_compute) && + NS_TO_JIFFIES(p->runtime + sleep_time) < RR_INTERVAL())) { + p->flags &= ~PF_FORKED; + if (p->slice - total_run < 1) { + p->totalrun = 0; + dec_burst(p); + } else { + p->totalrun = ns_totalrun; + p->slice -= total_run; } - } + } else { + if (!(p->flags & PF_UISLEEP)) + inc_burst(p); + p->runtime = 0; + p->totalrun = 0; } - - p->prio = effective_prio(p); } /* * activate_task - move a task to the runqueue and do priority recalculation - * - * Update all the scheduling statistics stuff. (sleep average - * calculation, priority modifiers, etc.) */ static void activate_task(task_t *p, runqueue_t *rq, int local) { - unsigned long long now; - - now = sched_clock(); + unsigned long long now = sched_clock(); #ifdef CONFIG_SMP if (!local) { /* Compensate for drifting sched_clock */ @@ -472,33 +358,12 @@ + rq->timestamp_last_tick; } #endif - + p->slice = slice(p); recalc_task_prio(p, now); - - /* - * This checks to make sure it's not an uninterruptible task - * that is now waking up. - */ - if (!p->activated) { - /* - * Tasks which were woken up by interrupts (ie. hw events) - * are most likely of interactive nature. So we give them - * the credit of extending their sleep time to the period - * of time they spend on the runqueue, waiting for execution - * on a CPU, first time around: - */ - if (in_interrupt()) - p->activated = 2; - else { - /* - * Normal first-time wakeups get a credit too for - * on-runqueue time, but it will be weighted down: - */ - p->activated = 1; - } - } + p->flags &= ~PF_UISLEEP; + p->prio = effective_prio(p); + p->time_slice = RR_INTERVAL(); p->timestamp = now; - __activate_task(p, rq); } @@ -508,10 +373,11 @@ static void deactivate_task(struct task_struct *p, runqueue_t *rq) { rq->nr_running--; - if (p->state == TASK_UNINTERRUPTIBLE) + if (p->state == TASK_UNINTERRUPTIBLE) { + p->flags |= PF_UISLEEP; rq->nr_uninterruptible++; - dequeue_task(p, p->array); - p->array = NULL; + } + dequeue_task(p, rq); } /* @@ -584,7 +450,7 @@ * If the task is not on a runqueue (and not running), then * it is sufficient to simply update the task's cpu field. */ - if (!p->array && !task_running(rq, p)) { + if (!task_queued(p) && !task_running(rq, p)) { set_task_cpu(p, dest_cpu); return 0; } @@ -615,7 +481,7 @@ repeat: rq = task_rq_lock(p, &flags); /* Must be off runqueue entirely, not preempted. */ - if (unlikely(p->array)) { + if (unlikely(task_queued(p))) { /* If it's preempted, we yield. It could be a while. */ preempted = !task_running(rq, p); task_rq_unlock(rq, &flags); @@ -713,6 +579,26 @@ } #endif +/* + * cache_delay is the time preemption is delayed in sched_compute mode + * and is set to 5*cache_decay_ticks + */ +static int cache_delay; + +static int task_preempts_curr(struct task_struct *p, runqueue_t *rq) +{ + if (p->prio > rq->curr->prio) + return 0; + if (p->prio == rq->curr->prio && (p->slice < slice(p) || + rt_task(rq->curr) || !sched_interactive)) + return 0; + if (!sched_compute || rq->cache_ticks >= cache_delay || + rt_task(p)) + return 1; + rq->preempted = 1; + return 0; +} + /*** * try_to_wake_up - wake up a thread * @p: the to-be-woken-up thread @@ -744,7 +630,7 @@ if (!(old_state & state)) goto out; - if (p->array) + if (task_queued(p)) goto out_running; cpu = task_cpu(p); @@ -811,7 +697,7 @@ old_state = p->state; if (!(old_state & state)) goto out; - if (p->array) + if (task_queued(p)) goto out_running; this_cpu = smp_processor_id(); @@ -820,14 +706,8 @@ out_activate: #endif /* CONFIG_SMP */ - if (old_state == TASK_UNINTERRUPTIBLE) { + if (old_state == TASK_UNINTERRUPTIBLE) rq->nr_uninterruptible--; - /* - * Tasks on involuntary sleep don't earn - * sleep_avg beyond just interactive state. - */ - p->activated = -1; - } /* * Sync wakeups (i.e. those types of wakeups where the waker @@ -839,7 +719,7 @@ */ activate_task(p, rq, cpu == this_cpu); if (!sync || cpu != this_cpu) { - if (TASK_PREEMPTS_CURR(p, rq)) + if (task_preempts_curr(p, rq)) resched_task(rq->curr); } success = 1; @@ -879,7 +759,6 @@ */ p->state = TASK_RUNNING; INIT_LIST_HEAD(&p->run_list); - p->array = NULL; spin_lock_init(&p->switch_lock); #ifdef CONFIG_PREEMPT /* @@ -890,33 +769,6 @@ */ p->thread_info->preempt_count = 1; #endif - /* - * Share the timeslice between parent and child, thus the - * total amount of pending timeslices in the system doesn't change, - * resulting in more scheduling fairness. - */ - local_irq_disable(); - p->time_slice = (current->time_slice + 1) >> 1; - /* - * The remainder of the first timeslice might be recovered by - * the parent if the child exits early enough. - */ - p->first_time_slice = 1; - current->time_slice >>= 1; - p->timestamp = sched_clock(); - if (!current->time_slice) { - /* - * This case is rare, it happens when the parent has only - * a single jiffy left from its timeslice. Taking the - * runqueue lock is not a problem. - */ - current->time_slice = 1; - preempt_disable(); - scheduler_tick(0, 0); - local_irq_enable(); - preempt_enable(); - } else - local_irq_enable(); } /* @@ -930,66 +782,16 @@ unsigned long flags; runqueue_t *rq = task_rq_lock(current, &flags); - BUG_ON(p->state != TASK_RUNNING); - - /* - * We decrease the sleep average of forking parents - * and children as well, to keep max-interactive tasks - * from forking tasks that are max-interactive. + /* + * Forked process gets no burst to prevent fork bombs. */ - current->sleep_avg = JIFFIES_TO_NS(CURRENT_BONUS(current) * - PARENT_PENALTY / 100 * MAX_SLEEP_AVG / MAX_BONUS); - - p->sleep_avg = JIFFIES_TO_NS(CURRENT_BONUS(p) * - CHILD_PENALTY / 100 * MAX_SLEEP_AVG / MAX_BONUS); - - p->interactive_credit = 0; + p->burst = 0; + BUG_ON(p->state != TASK_RUNNING); - p->prio = effective_prio(p); set_task_cpu(p, smp_processor_id()); - if (unlikely(!current->array)) - __activate_task(p, rq); - else { - p->prio = current->prio; - list_add_tail(&p->run_list, ¤t->run_list); - p->array = current->array; - p->array->nr_active++; - rq->nr_running++; - } - task_rq_unlock(rq, &flags); -} - -/* - * Potentially available exiting-child timeslices are - * retrieved here - this way the parent does not get - * penalized for creating too many threads. - * - * (this cannot be used to 'generate' timeslices - * artificially, because any timeslice recovered here - * was given away by the parent in the first place.) - */ -void fastcall sched_exit(task_t * p) -{ - unsigned long flags; - runqueue_t *rq; - - local_irq_save(flags); - if (p->first_time_slice) { - p->parent->time_slice += p->time_slice; - if (unlikely(p->parent->time_slice > MAX_TIMESLICE)) - p->parent->time_slice = MAX_TIMESLICE; - } - local_irq_restore(flags); - /* - * If the child was a (relative-) CPU hog then decrease - * the sleep_avg of the parent as well. - */ - rq = task_rq_lock(p->parent, &flags); - if (p->sleep_avg < p->parent->sleep_avg) - p->parent->sleep_avg = p->parent->sleep_avg / - (EXIT_WEIGHT + 1) * EXIT_WEIGHT + p->sleep_avg / - (EXIT_WEIGHT + 1); + __activate_task(p, rq); + current->flags |= PF_FORKED; task_rq_unlock(rq, &flags); } @@ -1253,30 +1055,16 @@ double_rq_unlock(this_rq, rq); goto lock_again; } - /* - * We decrease the sleep average of forking parents - * and children as well, to keep max-interactive tasks - * from forking tasks that are max-interactive. - */ - current->sleep_avg = JIFFIES_TO_NS(CURRENT_BONUS(current) * - PARENT_PENALTY / 100 * MAX_SLEEP_AVG / MAX_BONUS); - - p->sleep_avg = JIFFIES_TO_NS(CURRENT_BONUS(p) * - CHILD_PENALTY / 100 * MAX_SLEEP_AVG / MAX_BONUS); - - p->interactive_credit = 0; p->prio = effective_prio(p); set_task_cpu(p, cpu); if (cpu == this_cpu) { - if (unlikely(!current->array)) + if (unlikely(!task_queued(current))) __activate_task(p, rq); else { p->prio = current->prio; list_add_tail(&p->run_list, ¤t->run_list); - p->array = current->array; - p->array->nr_active++; rq->nr_running++; } } else { @@ -1284,7 +1072,7 @@ p->timestamp = (p->timestamp - this_rq->timestamp_last_tick) + rq->timestamp_last_tick; __activate_task(p, rq); - if (TASK_PREEMPTS_CURR(p, rq)) + if (task_preempts_curr(p, rq)) resched_task(rq->curr); } @@ -1376,22 +1164,22 @@ * pull_task - move a task from a remote runqueue to the local runqueue. * Both runqueues must be locked. */ -static inline -void pull_task(runqueue_t *src_rq, prio_array_t *src_array, task_t *p, - runqueue_t *this_rq, prio_array_t *this_array, int this_cpu) +static inline +void pull_task(runqueue_t *src_rq, task_t *p, + runqueue_t *this_rq, int this_cpu) { - dequeue_task(p, src_array); + dequeue_task(p, src_rq); src_rq->nr_running--; set_task_cpu(p, this_cpu); this_rq->nr_running++; - enqueue_task(p, this_array); + enqueue_task(p, this_rq); p->timestamp = (p->timestamp - src_rq->timestamp_last_tick) + this_rq->timestamp_last_tick; /* * Note that idle threads have a prio of MAX_PRIO, for this test * to be always true for them. */ - if (TASK_PREEMPTS_CURR(p, this_rq)) + if (task_preempts_curr(p, this_rq)) resched_task(this_rq->curr); } @@ -1434,7 +1222,6 @@ unsigned long max_nr_move, struct sched_domain *sd, enum idle_type idle) { - prio_array_t *array, *dst_array; struct list_head *head, *curr; int idx, pulled = 0; task_t *tmp; @@ -1442,38 +1229,17 @@ if (max_nr_move <= 0 || busiest->nr_running <= 1) goto out; - /* - * We first consider expired tasks. Those will likely not be - * executed in the near future, and they are most likely to - * be cache-cold, thus switching CPUs has the least effect - * on them. - */ - if (busiest->expired->nr_active) { - array = busiest->expired; - dst_array = this_rq->expired; - } else { - array = busiest->active; - dst_array = this_rq->active; - } - -new_array: /* Start searching at priority 0: */ idx = 0; skip_bitmap: if (!idx) - idx = sched_find_first_bit(array->bitmap); + idx = sched_find_first_bit(busiest->bitmap); else - idx = find_next_bit(array->bitmap, MAX_PRIO, idx); - if (idx >= MAX_PRIO) { - if (array == busiest->expired && busiest->active->nr_active) { - array = busiest->active; - dst_array = this_rq->active; - goto new_array; - } + idx = find_next_bit(busiest->bitmap, MAX_PRIO, idx); + if (idx >= MAX_PRIO) goto out; - } - head = array->queue + idx; + head = busiest->queue + idx; curr = head->prev; skip_queue: tmp = list_entry(curr, task_t, run_list); @@ -1486,7 +1252,7 @@ idx++; goto skip_bitmap; } - pull_task(busiest, array, tmp, this_rq, dst_array, this_cpu); + pull_task(busiest, tmp, this_rq, this_cpu); pulled++; /* We only want to steal up to the prescribed number of tasks. */ @@ -1956,22 +1722,6 @@ EXPORT_PER_CPU_SYMBOL(kstat); /* - * We place interactive tasks back into the active array, if possible. - * - * To guarantee that this does not starve expired tasks we ignore the - * interactivity of a task if the first expired task had to wait more - * than a 'reasonable' amount of time. This deadline timeout is - * load-dependent, as the frequency of array switched decreases with - * increasing number of running tasks. We also ignore the interactivity - * if a better static_prio task has expired: - */ -#define EXPIRED_STARVING(rq) \ - ((STARVATION_LIMIT && ((rq)->expired_timestamp && \ - (jiffies - (rq)->expired_timestamp >= \ - STARVATION_LIMIT * ((rq)->nr_running) + 1))) || \ - ((rq)->curr->static_prio > (rq)->best_expired_prio)) - -/* * This function gets called by the timer code, with HZ frequency. * We call it with interrupts disabled. * @@ -2014,79 +1764,41 @@ else cpustat->user += user_ticks; cpustat->system += sys_ticks; - - /* Task might have expired already, but not scheduled off yet */ - if (p->array != rq->active) { - set_tsk_need_resched(p); + /* + * SCHED_FIFO tasks never run out of timeslice. + */ + if (unlikely(p->policy == SCHED_FIFO)) goto out; - } + spin_lock(&rq->lock); + rq->cache_ticks++; /* - * The task was running during this tick - update the - * time slice counter. Note: we do not update a thread's - * priority until it either goes to sleep or uses up its - * timeslice. This makes it possible for interactive tasks - * to use up their timeslices at their highest priority levels. + * Tasks lose burst each time they use up a full slice(). */ - if (unlikely(rt_task(p))) { - /* - * RR tasks need a special form of timeslice management. - * FIFO tasks have no timeslices. - */ - if ((p->policy == SCHED_RR) && !--p->time_slice) { - p->time_slice = task_timeslice(p); - p->first_time_slice = 0; - set_tsk_need_resched(p); - - /* put it at the end of the queue: */ - dequeue_task(p, rq->active); - enqueue_task(p, rq->active); - } + if (!--p->slice) { + set_tsk_need_resched(p); + dequeue_task(p, rq); + dec_burst(p); + p->slice = slice(p); + p->prio = effective_prio(p); + p->time_slice = RR_INTERVAL(); + enqueue_task(p, rq); goto out_unlock; } + /* + * Tasks that run out of time_slice but still have slice left get + * requeued with a lower priority && RR_INTERVAL time_slice. + */ if (!--p->time_slice) { - dequeue_task(p, rq->active); set_tsk_need_resched(p); + dequeue_task(p, rq); p->prio = effective_prio(p); - p->time_slice = task_timeslice(p); - p->first_time_slice = 0; - - if (!rq->expired_timestamp) - rq->expired_timestamp = jiffies; - if (!TASK_INTERACTIVE(p) || EXPIRED_STARVING(rq)) { - enqueue_task(p, rq->expired); - if (p->static_prio < rq->best_expired_prio) - rq->best_expired_prio = p->static_prio; - } else - enqueue_task(p, rq->active); - } else { - /* - * Prevent a too long timeslice allowing a task to monopolize - * the CPU. We do this by splitting up the timeslice into - * smaller pieces. - * - * Note: this does not mean the task's timeslices expire or - * get lost in any way, they just might be preempted by - * another task of equal priority. (one with higher - * priority would have preempted this task already.) We - * requeue this task to the end of the list on this priority - * level, which is in essence a round-robin of tasks with - * equal priority. - * - * This only applies to tasks in the interactive - * delta range with at least TIMESLICE_GRANULARITY to requeue. - */ - if (TASK_INTERACTIVE(p) && !((task_timeslice(p) - - p->time_slice) % TIMESLICE_GRANULARITY(p)) && - (p->time_slice >= TIMESLICE_GRANULARITY(p)) && - (p->array == rq->active)) { - - dequeue_task(p, rq->active); - set_tsk_need_resched(p); - p->prio = effective_prio(p); - enqueue_task(p, rq->active); - } + p->time_slice = RR_INTERVAL(); + enqueue_task(p, rq); + goto out_unlock; } + if (rq->preempted && rq->cache_ticks >= cache_delay) + set_tsk_need_resched(p); out_unlock: spin_unlock(&rq->lock); out: @@ -2149,8 +1861,8 @@ * task from using an unfair proportion of the * physical cpu's resources. -ck */ - if (((smt_curr->time_slice * (100 - sd->per_cpu_gain) / 100) > - task_timeslice(p) || rt_task(smt_curr)) && + if (((smt_curr->slice * (100 - sd->per_cpu_gain) / 100) > + slice(p) || rt_task(smt_curr)) && p->mm && smt_curr->mm && !rt_task(p)) ret = 1; @@ -2159,8 +1871,8 @@ * or wake it up if it has been put to sleep for priority * reasons. */ - if ((((p->time_slice * (100 - sd->per_cpu_gain) / 100) > - task_timeslice(smt_curr) || rt_task(p)) && + if ((((p->slice * (100 - sd->per_cpu_gain) / 100) > + slice(smt_curr) || rt_task(p)) && smt_curr->mm && p->mm && !rt_task(smt_curr)) || (smt_curr == smt_rq->idle && smt_rq->nr_running)) resched_task(smt_curr); @@ -2186,10 +1898,8 @@ long *switch_count; task_t *prev, *next; runqueue_t *rq; - prio_array_t *array; struct list_head *queue; unsigned long long now; - unsigned long run_time; int cpu, idx; /* @@ -2211,19 +1921,8 @@ release_kernel_lock(prev); now = sched_clock(); - if (likely(now - prev->timestamp < NS_MAX_SLEEP_AVG)) - run_time = now - prev->timestamp; - else - run_time = NS_MAX_SLEEP_AVG; - - /* - * Tasks with interactive credits get charged less run_time - * at high sleep_avg to delay them losing their interactive - * status - */ - if (HIGH_CREDIT(prev)) - run_time /= (CURRENT_BONUS(prev) ? : 1); + prev->runtime = now - prev->timestamp; spin_lock_irq(&rq->lock); /* @@ -2245,59 +1944,32 @@ idle_balance(cpu, rq); if (!rq->nr_running) { next = rq->idle; - rq->expired_timestamp = 0; wake_sleeping_dependent(cpu, rq); goto switch_tasks; } } - array = rq->active; - if (unlikely(!array->nr_active)) { - /* - * Switch the active and expired arrays. - */ - rq->active = rq->expired; - rq->expired = array; - array = rq->active; - rq->expired_timestamp = 0; - rq->best_expired_prio = MAX_PRIO; - } - - idx = sched_find_first_bit(array->bitmap); - queue = array->queue + idx; + idx = sched_find_first_bit(rq->bitmap); + queue = rq->queue + idx; next = list_entry(queue->next, task_t, run_list); - if (dependent_sleeper(cpu, rq, next)) { + if (dependent_sleeper(cpu, rq, next)) next = rq->idle; - goto switch_tasks; - } - - if (!rt_task(next) && next->activated > 0) { - unsigned long long delta = now - next->timestamp; - - if (next->activated == 1) - delta = delta * (ON_RUNQUEUE_WEIGHT * 128 / 100) / 128; - - array = next->array; - dequeue_task(next, array); - recalc_task_prio(next, next->timestamp + delta); - enqueue_task(next, array); - } - next->activated = 0; switch_tasks: prefetch(next); clear_tsk_need_resched(prev); RCU_qsctr(task_cpu(prev))++; - - prev->sleep_avg -= run_time; - if ((long)prev->sleep_avg <= 0) { - prev->sleep_avg = 0; - if (!(HIGH_CREDIT(prev) || LOW_CREDIT(prev))) - prev->interactive_credit--; - } prev->timestamp = now; + if (next->flags & PF_YIELDED) { + next->flags &= ~PF_YIELDED; + dequeue_task(next, rq); + next->prio = effective_prio(next); + enqueue_task_head(next, rq); + } if (likely(prev != next)) { + rq->preempted = 0; + rq->cache_ticks = 0; next->timestamp = now; rq->nr_switches++; rq->curr = next; @@ -2560,9 +2232,8 @@ void set_user_nice(task_t *p, long nice) { unsigned long flags; - prio_array_t *array; runqueue_t *rq; - int old_prio, new_prio, delta; + int queued, old_prio, new_prio, delta; if (TASK_NICE(p) == nice || nice < -20 || nice > 19) return; @@ -2581,9 +2252,8 @@ p->static_prio = NICE_TO_PRIO(nice); goto out_unlock; } - array = p->array; - if (array) - dequeue_task(p, array); + if ((queued = task_queued(p))) + dequeue_task(p, rq); old_prio = p->prio; new_prio = NICE_TO_PRIO(nice); @@ -2591,8 +2261,8 @@ p->static_prio = NICE_TO_PRIO(nice); p->prio += delta; - if (array) { - enqueue_task(p, array); + if (queued) { + enqueue_task(p, rq); /* * If the task increased its priority or is running and * lowered its priority, then reschedule its CPU: @@ -2697,7 +2367,7 @@ /* Actually do priority change: must hold rq lock. */ static void __setscheduler(struct task_struct *p, int policy, int prio) { - BUG_ON(p->array); + BUG_ON(task_queued(p)); p->policy = policy; p->rt_priority = prio; if (policy != SCHED_NORMAL) @@ -2713,8 +2383,7 @@ { struct sched_param lp; int retval = -EINVAL; - int oldprio; - prio_array_t *array; + int queued, oldprio; unsigned long flags; runqueue_t *rq; task_t *p; @@ -2774,13 +2443,12 @@ if (retval) goto out_unlock; - array = p->array; - if (array) + if ((queued = task_queued(p))) deactivate_task(p, task_rq(p)); retval = 0; oldprio = p->prio; __setscheduler(p, policy, lp.sched_priority); - if (array) { + if (queued) { __activate_task(p, task_rq(p)); /* * Reschedule if we are currently running on this runqueue and @@ -2790,7 +2458,7 @@ if (task_running(rq, p)) { if (p->prio > oldprio) resched_task(rq->curr); - } else if (TASK_PREEMPTS_CURR(p, rq)) + } else if (task_preempts_curr(p, rq)) resched_task(rq->curr); } @@ -2998,28 +2666,21 @@ /** * sys_sched_yield - yield the current processor to other threads. * - * this function yields the current CPU by moving the calling thread - * to the expired array. If there are no other threads running on this * CPU then this function will return. */ asmlinkage long sys_sched_yield(void) { runqueue_t *rq = this_rq_lock(); - prio_array_t *array = current->array; - prio_array_t *target = rq->expired; - /* - * We implement yielding by moving the task into the expired - * queue. - * - * (special rule: RT tasks will just roundrobin in the active - * array.) - */ - if (unlikely(rt_task(current))) - target = rq->active; - - dequeue_task(current, array); - enqueue_task(current, target); + dequeue_task(current, rq); + current->slice = slice(current); + current->time_slice = RR_INTERVAL(); + if (likely(!rt_task(current))) { + current->flags |= PF_YIELDED; + current->prio = MAX_PRIO - 1; + } + current->burst = 0; + enqueue_task(current, rq); /* * Since we are going to call schedule() anyway, there's @@ -3158,7 +2819,7 @@ goto out_unlock; jiffies_to_timespec(p->policy & SCHED_FIFO ? - 0 : task_timeslice(p), &t); + 0 : slice(p), &t); read_unlock(&tasklist_lock); retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; out_nounlock: @@ -3276,9 +2937,9 @@ idle_rq->curr = idle_rq->idle = idle; deactivate_task(idle, rq); - idle->array = NULL; idle->prio = MAX_PRIO; idle->state = TASK_RUNNING; + idle->burst = 0; set_task_cpu(idle, cpu); double_rq_unlock(idle_rq, rq); set_tsk_need_resched(idle); @@ -3388,7 +3049,7 @@ goto out; set_task_cpu(p, dest_cpu); - if (p->array) { + if (task_queued(p)) { /* * Sync timestamp with rq_dest's before activating. * The same thing could be achieved by doing this step @@ -3399,7 +3060,7 @@ + rq_dest->timestamp_last_tick; deactivate_task(p, rq_src); activate_task(p, rq_dest, 0); - if (TASK_PREEMPTS_CURR(p, rq_dest)) + if (task_preempts_curr(p, rq_dest)) resched_task(rq_dest->curr); } @@ -3910,7 +3571,7 @@ void __init sched_init(void) { runqueue_t *rq; - int i, j, k; + int i, j; #ifdef CONFIG_SMP /* Set up an initial dummy domain for early boot */ @@ -3930,13 +3591,12 @@ #endif for (i = 0; i < NR_CPUS; i++) { - prio_array_t *array; - rq = cpu_rq(i); spin_lock_init(&rq->lock); - rq->active = rq->arrays; - rq->expired = rq->arrays + 1; - rq->best_expired_prio = MAX_PRIO; + + cache_delay = 10 * HZ / 1000; + rq->cache_ticks = 0; + rq->preempted = 0; #ifdef CONFIG_SMP rq->sd = &sched_domain_init; @@ -3945,18 +3605,16 @@ rq->push_cpu = 0; rq->migration_thread = NULL; INIT_LIST_HEAD(&rq->migration_queue); + cache_delay = cache_decay_ticks * 5; #endif atomic_set(&rq->nr_iowait, 0); - - for (j = 0; j < 2; j++) { - array = rq->arrays + j; - for (k = 0; k < MAX_PRIO; k++) { - INIT_LIST_HEAD(array->queue + k); - __clear_bit(k, array->bitmap); - } - // delimiter for bitsearch - __set_bit(MAX_PRIO, array->bitmap); - } + for (j = 0; j <= MAX_PRIO; j++) + INIT_LIST_HEAD(&rq->queue[j]); + memset(rq->bitmap, 0, BITS_TO_LONGS(MAX_PRIO+1)*sizeof(long)); + /* + * delimiter for bitsearch + */ + __set_bit(MAX_PRIO, rq->bitmap); } /* * We have to do a little magic to get the first Index: linux-2.6.8-rc2-bk7/kernel/sysctl.c =================================================================== --- linux-2.6.8-rc2-bk7.orig/kernel/sysctl.c 2004-07-29 09:48:36.013383780 +1000 +++ linux-2.6.8-rc2-bk7/kernel/sysctl.c 2004-07-29 09:52:00.973204900 +1000 @@ -620,6 +620,22 @@ .mode = 0444, .proc_handler = &proc_dointvec, }, + { + .ctl_name = KERN_INTERACTIVE, + .procname = "interactive", + .data = &sched_interactive, + .maxlen = sizeof (int), + .mode = 0644, + .proc_handler = &proc_dointvec, + }, + { + .ctl_name = KERN_COMPUTE, + .procname = "compute", + .data = &sched_compute, + .maxlen = sizeof (int), + .mode = 0644, + .proc_handler = &proc_dointvec, + }, { .ctl_name = 0 } };