/*- * Copyright (c) 2002-2007, Jeffrey Roberson * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice unmodified, this list of conditions, and the following * disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include __FBSDID("$FreeBSD$"); #include "opt_hwpmc_hooks.h" #include "opt_sched.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef KTRACE #include #include #endif #ifdef HWPMC_HOOKS #include #endif #include #include #ifndef PREEMPTION #error "SCHED_ULE requires options PREEMPTION" #endif /* * TODO: * Pick idle from affinity group or self group first. * Implement pick_score. */ #define KTR_ULE 0x0 /* Enable for pickpri debugging. */ /* * Thread scheduler specific section. */ struct td_sched { TAILQ_ENTRY(td_sched) ts_procq; /* (j/z) Run queue. */ int ts_flags; /* (j) TSF_* flags. */ struct thread *ts_thread; /* (*) Active associated thread. */ u_char ts_rqindex; /* (j) Run queue index. */ int ts_slptime; int ts_slice; struct runq *ts_runq; u_char ts_cpu; /* CPU that we have affinity for. */ /* The following variables are only used for pctcpu calculation */ int ts_ltick; /* Last tick that we were running on */ int ts_ftick; /* First tick that we were running on */ int ts_ticks; /* Tick count */ #ifdef SMP int ts_rltick; /* Real last tick, for affinity. */ #endif /* originally from kg_sched */ u_int skg_slptime; /* Number of ticks we vol. slept */ u_int skg_runtime; /* Number of ticks we were running */ }; /* flags kept in ts_flags */ #define TSF_BOUND 0x0001 /* Thread can not migrate. */ #define TSF_XFERABLE 0x0002 /* Thread was added as transferable. */ static struct td_sched td_sched0; /* * Cpu percentage computation macros and defines. * * SCHED_TICK_SECS: Number of seconds to average the cpu usage across. * SCHED_TICK_TARG: Number of hz ticks to average the cpu usage across. * SCHED_TICK_MAX: Maximum number of ticks before scaling back. * SCHED_TICK_SHIFT: Shift factor to avoid rounding away results. * SCHED_TICK_HZ: Compute the number of hz ticks for a given ticks count. * SCHED_TICK_TOTAL: Gives the amount of time we've been recording ticks. */ #define SCHED_TICK_SECS 10 #define SCHED_TICK_TARG (hz * SCHED_TICK_SECS) #define SCHED_TICK_MAX (SCHED_TICK_TARG + hz) #define SCHED_TICK_SHIFT 10 #define SCHED_TICK_HZ(ts) ((ts)->ts_ticks >> SCHED_TICK_SHIFT) #define SCHED_TICK_TOTAL(ts) (max((ts)->ts_ltick - (ts)->ts_ftick, hz)) /* * These macros determine priorities for non-interactive threads. They are * assigned a priority based on their recent cpu utilization as expressed * by the ratio of ticks to the tick total. NHALF priorities at the start * and end of the MIN to MAX timeshare range are only reachable with negative * or positive nice respectively. * * PRI_RANGE: Priority range for utilization dependent priorities. * PRI_NRESV: Number of nice values. * PRI_TICKS: Compute a priority in PRI_RANGE from the ticks count and total. * PRI_NICE: Determines the part of the priority inherited from nice. */ #define SCHED_PRI_NRESV (PRIO_MAX - PRIO_MIN) #define SCHED_PRI_NHALF (SCHED_PRI_NRESV / 2) #define SCHED_PRI_MIN (PRI_MIN_TIMESHARE + SCHED_PRI_NHALF) #define SCHED_PRI_MAX (PRI_MAX_TIMESHARE - SCHED_PRI_NHALF) #define SCHED_PRI_RANGE (SCHED_PRI_MAX - SCHED_PRI_MIN + 1) #define SCHED_PRI_TICKS(ts) \ (SCHED_TICK_HZ((ts)) / \ (roundup(SCHED_TICK_TOTAL((ts)), SCHED_PRI_RANGE) / SCHED_PRI_RANGE)) #define SCHED_PRI_NICE(nice) (nice) /* * These determine the interactivity of a process. Interactivity differs from * cpu utilization in that it expresses the voluntary time slept vs time ran * while cpu utilization includes all time not running. This more accurately * models the intent of the thread. * * SLP_RUN_MAX: Maximum amount of sleep time + run time we'll accumulate * before throttling back. * SLP_RUN_FORK: Maximum slp+run time to inherit at fork time. * INTERACT_MAX: Maximum interactivity value. Smaller is better. * INTERACT_THRESH: Threshhold for placement on the current runq. */ #define SCHED_SLP_RUN_MAX ((hz * 5) << SCHED_TICK_SHIFT) #define SCHED_SLP_RUN_FORK ((hz / 2) << SCHED_TICK_SHIFT) #define SCHED_INTERACT_MAX (100) #define SCHED_INTERACT_HALF (SCHED_INTERACT_MAX / 2) #define SCHED_INTERACT_THRESH (30) /* * tickincr: Converts a stathz tick into a hz domain scaled by * the shift factor. Without the shift the error rate * due to rounding would be unacceptably high. * realstathz: stathz is sometimes 0 and run off of hz. * sched_slice: Runtime of each thread before rescheduling. */ static int sched_interact = SCHED_INTERACT_THRESH; static int realstathz; static int tickincr; static int sched_slice; /* * tdq - per processor runqs and statistics. */ struct tdq { struct runq tdq_idle; /* Queue of IDLE threads. */ struct runq tdq_timeshare; /* timeshare run queue. */ struct runq tdq_realtime; /* real-time run queue. */ u_char tdq_idx; /* Current insert index. */ u_char tdq_ridx; /* Current removal index. */ short tdq_flags; /* Thread queue flags */ int tdq_load; /* Aggregate load. */ #ifdef SMP int tdq_transferable; LIST_ENTRY(tdq) tdq_siblings; /* Next in tdq group. */ struct tdq_group *tdq_group; /* Our processor group. */ #else int tdq_sysload; /* For loadavg, !ITHD load. */ #endif }; #define TDQF_BUSY 0x0001 /* Queue is marked as busy */ #ifdef SMP /* * tdq groups are groups of processors which can cheaply share threads. When * one processor in the group goes idle it will check the runqs of the other * processors in its group prior to halting and waiting for an interrupt. * These groups are suitable for SMT (Symetric Multi-Threading) and not NUMA. * In a numa environment we'd want an idle bitmap per group and a two tiered * load balancer. */ struct tdq_group { int tdg_cpus; /* Count of CPUs in this tdq group. */ cpumask_t tdg_cpumask; /* Mask of cpus in this group. */ cpumask_t tdg_idlemask; /* Idle cpus in this group. */ cpumask_t tdg_mask; /* Bit mask for first cpu. */ int tdg_load; /* Total load of this group. */ int tdg_transferable; /* Transferable load of this group. */ LIST_HEAD(, tdq) tdg_members; /* Linked list of all members. */ }; #define SCHED_AFFINITY_DEFAULT (hz / 100) #define SCHED_AFFINITY(ts) ((ts)->ts_rltick > ticks - affinity) /* * Run-time tunables. */ static int rebalance = 0; static int pick_pri = 0; static int affinity; static int tryself = 1; static int tryselfidle = 1; static int ipi_ast = 0; static int ipi_preempt = 1; static int ipi_thresh = PRI_MIN_KERN; static int steal_htt = 1; static int steal_busy = 1; static int busy_thresh = 4; static int topology = 0; /* * One thread queue per processor. */ static volatile cpumask_t tdq_idle; static volatile cpumask_t tdq_busy; static int tdg_maxid; static struct tdq tdq_cpu[MAXCPU]; static struct tdq_group tdq_groups[MAXCPU]; static int bal_tick; static int gbal_tick; static int balance_groups; #define TDQ_SELF() (&tdq_cpu[PCPU_GET(cpuid)]) #define TDQ_CPU(x) (&tdq_cpu[(x)]) #define TDQ_ID(x) ((x) - tdq_cpu) #define TDQ_GROUP(x) (&tdq_groups[(x)]) #else /* !SMP */ static struct tdq tdq_cpu; #define TDQ_ID(x) (0) #define TDQ_SELF() (&tdq_cpu) #define TDQ_CPU(x) (&tdq_cpu) #endif static void sched_priority(struct thread *); static void sched_thread_priority(struct thread *, u_char); static int sched_interact_score(struct thread *); static void sched_interact_update(struct thread *); static void sched_interact_fork(struct thread *); static void sched_pctcpu_update(struct td_sched *); static inline void sched_pin_td(struct thread *td); static inline void sched_unpin_td(struct thread *td); /* Operations on per processor queues */ static struct td_sched * tdq_choose(struct tdq *); static void tdq_setup(struct tdq *); static void tdq_load_add(struct tdq *, struct td_sched *); static void tdq_load_rem(struct tdq *, struct td_sched *); static __inline void tdq_runq_add(struct tdq *, struct td_sched *, int); static __inline void tdq_runq_rem(struct tdq *, struct td_sched *); void tdq_print(int cpu); static void runq_print(struct runq *rq); #ifdef SMP static int tdq_pickidle(struct tdq *, struct td_sched *); static int tdq_pickpri(struct tdq *, struct td_sched *, int); static struct td_sched *runq_steal(struct runq *); static void sched_balance(void); static void sched_balance_groups(void); static void sched_balance_group(struct tdq_group *); static void sched_balance_pair(struct tdq *, struct tdq *); static void sched_smp_tick(struct thread *); static void tdq_move(struct tdq *, int); static int tdq_idled(struct tdq *); static void tdq_notify(struct td_sched *); static struct td_sched *tdq_steal(struct tdq *, int); #define THREAD_CAN_MIGRATE(td) ((td)->td_pinned == 0) #endif static void sched_setup(void *dummy); SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL) static void sched_initticks(void *dummy); SYSINIT(sched_initticks, SI_SUB_CLOCKS, SI_ORDER_THIRD, sched_initticks, NULL) static inline void sched_pin_td(struct thread *td) { td->td_pinned++; } static inline void sched_unpin_td(struct thread *td) { td->td_pinned--; } static void runq_print(struct runq *rq) { struct rqhead *rqh; struct td_sched *ts; int pri; int j; int i; for (i = 0; i < RQB_LEN; i++) { printf("\t\trunq bits %d 0x%zx\n", i, rq->rq_status.rqb_bits[i]); for (j = 0; j < RQB_BPW; j++) if (rq->rq_status.rqb_bits[i] & (1ul << j)) { pri = j + (i << RQB_L2BPW); rqh = &rq->rq_queues[pri]; TAILQ_FOREACH(ts, rqh, ts_procq) { printf("\t\t\ttd %p(%s) priority %d rqindex %d pri %d\n", ts->ts_thread, ts->ts_thread->td_proc->p_comm, ts->ts_thread->td_priority, ts->ts_rqindex, pri); } } } } void tdq_print(int cpu) { struct tdq *tdq; tdq = TDQ_CPU(cpu); printf("tdq:\n"); printf("\tload: %d\n", tdq->tdq_load); printf("\ttimeshare idx: %d\n", tdq->tdq_idx); printf("\ttimeshare ridx: %d\n", tdq->tdq_ridx); printf("\trealtime runq:\n"); runq_print(&tdq->tdq_realtime); printf("\ttimeshare runq:\n"); runq_print(&tdq->tdq_timeshare); printf("\tidle runq:\n"); runq_print(&tdq->tdq_idle); #ifdef SMP printf("\tload transferable: %d\n", tdq->tdq_transferable); #endif } static __inline void tdq_runq_add(struct tdq *tdq, struct td_sched *ts, int flags) { #ifdef SMP if (THREAD_CAN_MIGRATE(ts->ts_thread)) { tdq->tdq_transferable++; tdq->tdq_group->tdg_transferable++; ts->ts_flags |= TSF_XFERABLE; if (tdq->tdq_transferable >= busy_thresh && (tdq->tdq_flags & TDQF_BUSY) == 0) { tdq->tdq_flags |= TDQF_BUSY; atomic_set_int(&tdq_busy, 1 << TDQ_ID(tdq)); } } #endif if (ts->ts_runq == &tdq->tdq_timeshare) { u_char pri; pri = ts->ts_thread->td_priority; KASSERT(pri <= PRI_MAX_TIMESHARE && pri >= PRI_MIN_TIMESHARE, ("Invalid priority %d on timeshare runq", pri)); /* * This queue contains only priorities between MIN and MAX * realtime. Use the whole queue to represent these values. */ #define TS_RQ_PPQ (((PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE) + 1) / RQ_NQS) if ((flags & SRQ_BORROWING) == 0) { pri = (pri - PRI_MIN_TIMESHARE) / TS_RQ_PPQ; pri = (pri + tdq->tdq_idx) % RQ_NQS; /* * This effectively shortens the queue by one so we * can have a one slot difference between idx and * ridx while we wait for threads to drain. */ if (tdq->tdq_ridx != tdq->tdq_idx && pri == tdq->tdq_ridx) pri = (unsigned char)(pri - 1) % RQ_NQS; } else pri = tdq->tdq_ridx; runq_add_pri(ts->ts_runq, ts, pri, flags); } else runq_add(ts->ts_runq, ts, flags); } static __inline void tdq_runq_rem(struct tdq *tdq, struct td_sched *ts) { #ifdef SMP if (ts->ts_flags & TSF_XFERABLE) { tdq->tdq_transferable--; tdq->tdq_group->tdg_transferable--; ts->ts_flags &= ~TSF_XFERABLE; if (tdq->tdq_transferable < busy_thresh && (tdq->tdq_flags & TDQF_BUSY)) { atomic_clear_int(&tdq_busy, 1 << TDQ_ID(tdq)); tdq->tdq_flags &= ~TDQF_BUSY; } } #endif if (ts->ts_runq == &tdq->tdq_timeshare) { if (tdq->tdq_idx != tdq->tdq_ridx) runq_remove_idx(ts->ts_runq, ts, &tdq->tdq_ridx); else runq_remove_idx(ts->ts_runq, ts, NULL); /* * For timeshare threads we update the priority here so * the priority reflects the time we've been sleeping. */ ts->ts_ltick = ticks; sched_pctcpu_update(ts); sched_priority(ts->ts_thread); } else runq_remove(ts->ts_runq, ts); } static void tdq_load_add(struct tdq *tdq, struct td_sched *ts) { int class; mtx_assert(&sched_lock, MA_OWNED); class = PRI_BASE(ts->ts_thread->td_pri_class); tdq->tdq_load++; CTR2(KTR_SCHED, "cpu %jd load: %d", TDQ_ID(tdq), tdq->tdq_load); if (class != PRI_ITHD && (ts->ts_thread->td_proc->p_flag & P_NOLOAD) == 0) #ifdef SMP tdq->tdq_group->tdg_load++; #else tdq->tdq_sysload++; #endif } static void tdq_load_rem(struct tdq *tdq, struct td_sched *ts) { int class; mtx_assert(&sched_lock, MA_OWNED); class = PRI_BASE(ts->ts_thread->td_pri_class); if (class != PRI_ITHD && (ts->ts_thread->td_proc->p_flag & P_NOLOAD) == 0) #ifdef SMP tdq->tdq_group->tdg_load--; #else tdq->tdq_sysload--; #endif tdq->tdq_load--; CTR1(KTR_SCHED, "load: %d", tdq->tdq_load); ts->ts_runq = NULL; } #ifdef SMP static void sched_smp_tick(struct thread *td) { struct tdq *tdq; tdq = TDQ_SELF(); if (rebalance) { if (ticks >= bal_tick) sched_balance(); if (ticks >= gbal_tick && balance_groups) sched_balance_groups(); } td->td_sched->ts_rltick = ticks; } /* * sched_balance is a simple CPU load balancing algorithm. It operates by * finding the least loaded and most loaded cpu and equalizing their load * by migrating some processes. * * Dealing only with two CPUs at a time has two advantages. Firstly, most * installations will only have 2 cpus. Secondly, load balancing too much at * once can have an unpleasant effect on the system. The scheduler rarely has * enough information to make perfect decisions. So this algorithm chooses * algorithm simplicity and more gradual effects on load in larger systems. * * It could be improved by considering the priorities and slices assigned to * each task prior to balancing them. There are many pathological cases with * any approach and so the semi random algorithm below may work as well as any. * */ static void sched_balance(void) { struct tdq_group *high; struct tdq_group *low; struct tdq_group *tdg; int cnt; int i; bal_tick = ticks + (random() % (hz * 2)); if (smp_started == 0) return; low = high = NULL; i = random() % (tdg_maxid + 1); for (cnt = 0; cnt <= tdg_maxid; cnt++) { tdg = TDQ_GROUP(i); /* * Find the CPU with the highest load that has some * threads to transfer. */ if ((high == NULL || tdg->tdg_load > high->tdg_load) && tdg->tdg_transferable) high = tdg; if (low == NULL || tdg->tdg_load < low->tdg_load) low = tdg; if (++i > tdg_maxid) i = 0; } if (low != NULL && high != NULL && high != low) sched_balance_pair(LIST_FIRST(&high->tdg_members), LIST_FIRST(&low->tdg_members)); } static void sched_balance_groups(void) { int i; gbal_tick = ticks + (random() % (hz * 2)); mtx_assert(&sched_lock, MA_OWNED); if (smp_started) for (i = 0; i <= tdg_maxid; i++) sched_balance_group(TDQ_GROUP(i)); } static void sched_balance_group(struct tdq_group *tdg) { struct tdq *tdq; struct tdq *high; struct tdq *low; int load; if (tdg->tdg_transferable == 0) return; low = NULL; high = NULL; LIST_FOREACH(tdq, &tdg->tdg_members, tdq_siblings) { load = tdq->tdq_load; if (high == NULL || load > high->tdq_load) high = tdq; if (low == NULL || load < low->tdq_load) low = tdq; } if (high != NULL && low != NULL && high != low) sched_balance_pair(high, low); } static void sched_balance_pair(struct tdq *high, struct tdq *low) { int transferable; int high_load; int low_load; int move; int diff; int i; /* * If we're transfering within a group we have to use this specific * tdq's transferable count, otherwise we can steal from other members * of the group. */ if (high->tdq_group == low->tdq_group) { transferable = high->tdq_transferable; high_load = high->tdq_load; low_load = low->tdq_load; } else { transferable = high->tdq_group->tdg_transferable; high_load = high->tdq_group->tdg_load; low_load = low->tdq_group->tdg_load; } if (transferable == 0) return; /* * Determine what the imbalance is and then adjust that to how many * threads we actually have to give up (transferable). */ diff = high_load - low_load; move = diff / 2; if (diff & 0x1) move++; move = min(move, transferable); for (i = 0; i < move; i++) tdq_move(high, TDQ_ID(low)); return; } static void tdq_move(struct tdq *from, int cpu) { struct tdq *tdq; struct tdq *to; struct td_sched *ts; tdq = from; to = TDQ_CPU(cpu); ts = tdq_steal(tdq, 1); if (ts == NULL) { struct tdq_group *tdg; tdg = tdq->tdq_group; LIST_FOREACH(tdq, &tdg->tdg_members, tdq_siblings) { if (tdq == from || tdq->tdq_transferable == 0) continue; ts = tdq_steal(tdq, 1); break; } if (ts == NULL) panic("tdq_move: No threads available with a " "transferable count of %d\n", tdg->tdg_transferable); } if (tdq == to) return; sched_rem(ts->ts_thread); ts->ts_cpu = cpu; sched_pin_td(ts->ts_thread); sched_add(ts->ts_thread, SRQ_YIELDING); sched_unpin_td(ts->ts_thread); } static int tdq_idled(struct tdq *tdq) { struct tdq_group *tdg; struct tdq *steal; struct td_sched *ts; tdg = tdq->tdq_group; /* * If we're in a cpu group, try and steal threads from another cpu in * the group before idling. */ if (steal_htt && tdg->tdg_cpus > 1 && tdg->tdg_transferable) { LIST_FOREACH(steal, &tdg->tdg_members, tdq_siblings) { if (steal == tdq || steal->tdq_transferable == 0) continue; ts = tdq_steal(steal, 0); if (ts) goto steal; } } if (steal_busy) { while (tdq_busy) { int cpu; cpu = ffs(tdq_busy); if (cpu == 0) break; cpu--; steal = TDQ_CPU(cpu); if (steal->tdq_transferable == 0) continue; ts = tdq_steal(steal, 1); if (ts == NULL) continue; CTR5(KTR_ULE, "tdq_idled: stealing td %p(%s) pri %d from %d busy 0x%X", ts->ts_thread, ts->ts_thread->td_proc->p_comm, ts->ts_thread->td_priority, cpu, tdq_busy); goto steal; } } /* * We only set the idled bit when all of the cpus in the group are * idle. Otherwise we could get into a situation where a thread bounces * back and forth between two idle cores on seperate physical CPUs. */ tdg->tdg_idlemask |= PCPU_GET(cpumask); if (tdg->tdg_idlemask == tdg->tdg_cpumask) atomic_set_int(&tdq_idle, tdg->tdg_mask); return (1); steal: sched_rem(ts->ts_thread); ts->ts_cpu = PCPU_GET(cpuid); sched_pin_td(ts->ts_thread); sched_add(ts->ts_thread, SRQ_YIELDING); sched_unpin_td(ts->ts_thread); return (0); } static void tdq_notify(struct td_sched *ts) { struct thread *ctd; struct pcpu *pcpu; int cpri; int pri; int cpu; cpu = ts->ts_cpu; pri = ts->ts_thread->td_priority; pcpu = pcpu_find(cpu); ctd = pcpu->pc_curthread; cpri = ctd->td_priority; /* * If our priority is not better than the current priority there is * nothing to do. */ if (pri > cpri) return; /* * Always IPI idle. */ if (cpri > PRI_MIN_IDLE) goto sendipi; /* * If we're realtime or better and there is timeshare or worse running * send an IPI. */ if (pri < PRI_MAX_REALTIME && cpri > PRI_MAX_REALTIME) goto sendipi; /* * Otherwise only IPI if we exceed the threshold. */ if (pri > ipi_thresh) return; sendipi: ctd->td_flags |= TDF_NEEDRESCHED; if (cpri < PRI_MIN_IDLE) { if (ipi_ast) ipi_selected(1 << cpu, IPI_AST); else if (ipi_preempt) ipi_selected(1 << cpu, IPI_PREEMPT); } else ipi_selected(1 << cpu, IPI_PREEMPT); } static struct td_sched * runq_steal(struct runq *rq) { struct rqhead *rqh; struct rqbits *rqb; struct td_sched *ts; int word; int bit; mtx_assert(&sched_lock, MA_OWNED); rqb = &rq->rq_status; for (word = 0; word < RQB_LEN; word++) { if (rqb->rqb_bits[word] == 0) continue; for (bit = 0; bit < RQB_BPW; bit++) { if ((rqb->rqb_bits[word] & (1ul << bit)) == 0) continue; rqh = &rq->rq_queues[bit + (word << RQB_L2BPW)]; TAILQ_FOREACH(ts, rqh, ts_procq) { if (THREAD_CAN_MIGRATE(ts->ts_thread)) return (ts); } } } return (NULL); } static struct td_sched * tdq_steal(struct tdq *tdq, int stealidle) { struct td_sched *ts; /* * Steal from next first to try to get a non-interactive task that * may not have run for a while. * XXX Need to effect steal order for timeshare threads. */ if ((ts = runq_steal(&tdq->tdq_realtime)) != NULL) return (ts); if ((ts = runq_steal(&tdq->tdq_timeshare)) != NULL) return (ts); if (stealidle) return (runq_steal(&tdq->tdq_idle)); return (NULL); } int tdq_pickidle(struct tdq *tdq, struct td_sched *ts) { struct tdq_group *tdg; int self; int cpu; self = PCPU_GET(cpuid); if (smp_started == 0) return (self); /* * If the current CPU has idled, just run it here. */ if ((tdq->tdq_group->tdg_idlemask & PCPU_GET(cpumask)) != 0) return (self); /* * Try the last group we ran on. */ tdg = TDQ_CPU(ts->ts_cpu)->tdq_group; cpu = ffs(tdg->tdg_idlemask); if (cpu) return (cpu - 1); /* * Search for an idle group. */ cpu = ffs(tdq_idle); if (cpu) return (cpu - 1); /* * XXX If there are no idle groups, check for an idle core. */ /* * No idle CPUs? */ return (self); } static int tdq_pickpri(struct tdq *tdq, struct td_sched *ts, int flags) { struct pcpu *pcpu; int lowpri; int lowcpu; int lowload; int load; int self; int pri; int cpu; self = PCPU_GET(cpuid); if (smp_started == 0) return (self); pri = ts->ts_thread->td_priority; /* * Regardless of affinity, if the last cpu is idle send it there. */ pcpu = pcpu_find(ts->ts_cpu); if (pcpu->pc_curthread->td_priority > PRI_MIN_IDLE) { CTR5(KTR_ULE, "ts_cpu %d idle, ltick %d ticks %d pri %d curthread %d", ts->ts_cpu, ts->ts_rltick, ticks, pri, pcpu->pc_curthread->td_priority); return (ts->ts_cpu); } /* * If we have affinity, try to place it on the cpu we last ran on. */ if (SCHED_AFFINITY(ts) && pcpu->pc_curthread->td_priority > pri) { CTR5(KTR_ULE, "affinity for %d, ltick %d ticks %d pri %d curthread %d", ts->ts_cpu, ts->ts_rltick, ticks, pri, pcpu->pc_curthread->td_priority); return (ts->ts_cpu); } /* * Try ourself first; If we're running something lower priority this * may have some locality with the waking thread and execute faster * here. */ if (tryself) { /* * If we're being awoken by an interrupt thread or the waker * is going right to sleep run here as well. */ if ((TDQ_SELF()->tdq_load == 1) && (flags & SRQ_YIELDING || curthread->td_pri_class == PRI_ITHD)) { CTR2(KTR_ULE, "tryself load %d flags %d", TDQ_SELF()->tdq_load, flags); return (self); } } /* * Look for an idle group. */ CTR1(KTR_ULE, "tdq_idle %X", tdq_idle); cpu = ffs(tdq_idle); if (cpu) return (cpu - 1); if (tryselfidle && pri < curthread->td_priority) { CTR1(KTR_ULE, "tryself %d", curthread->td_priority); return (self); } /* * Now search for the cpu running the lowest priority thread with * the least load. */ lowload = 0; lowpri = lowcpu = 0; for (cpu = 0; cpu <= mp_maxid; cpu++) { if (CPU_ABSENT(cpu)) continue; pcpu = pcpu_find(cpu); pri = pcpu->pc_curthread->td_priority; CTR4(KTR_ULE, "cpu %d pri %d lowcpu %d lowpri %d", cpu, pri, lowcpu, lowpri); if (pri < lowpri) continue; load = TDQ_CPU(cpu)->tdq_load; if (lowpri && lowpri == pri && load > lowload) continue; lowpri = pri; lowcpu = cpu; lowload = load; } return (lowcpu); } #endif /* SMP */ /* * Pick the highest priority task we have and return it. */ static struct td_sched * tdq_choose(struct tdq *tdq) { struct td_sched *ts; mtx_assert(&sched_lock, MA_OWNED); ts = runq_choose(&tdq->tdq_realtime); if (ts != NULL) { KASSERT(ts->ts_thread->td_priority <= PRI_MAX_REALTIME, ("tdq_choose: Invalid priority on realtime queue %d", ts->ts_thread->td_priority)); return (ts); } ts = runq_choose_from(&tdq->tdq_timeshare, tdq->tdq_ridx); if (ts != NULL) { KASSERT(ts->ts_thread->td_priority <= PRI_MAX_TIMESHARE && ts->ts_thread->td_priority >= PRI_MIN_TIMESHARE, ("tdq_choose: Invalid priority on timeshare queue %d", ts->ts_thread->td_priority)); return (ts); } ts = runq_choose(&tdq->tdq_idle); if (ts != NULL) { KASSERT(ts->ts_thread->td_priority >= PRI_MIN_IDLE, ("tdq_choose: Invalid priority on idle queue %d", ts->ts_thread->td_priority)); return (ts); } return (NULL); } static void tdq_setup(struct tdq *tdq) { runq_init(&tdq->tdq_realtime); runq_init(&tdq->tdq_timeshare); runq_init(&tdq->tdq_idle); tdq->tdq_load = 0; } static void sched_setup(void *dummy) { #ifdef SMP int i; #endif /* * To avoid divide-by-zero, we set realstathz a dummy value * in case which sched_clock() called before sched_initticks(). */ realstathz = hz; sched_slice = (realstathz/10); /* ~100ms */ tickincr = 1 << SCHED_TICK_SHIFT; #ifdef SMP balance_groups = 0; /* * Initialize the tdqs. */ for (i = 0; i < MAXCPU; i++) { struct tdq *tdq; tdq = &tdq_cpu[i]; tdq_setup(&tdq_cpu[i]); } if (smp_topology == NULL) { struct tdq_group *tdg; struct tdq *tdq; int cpus; for (cpus = 0, i = 0; i < MAXCPU; i++) { if (CPU_ABSENT(i)) continue; tdq = &tdq_cpu[i]; tdg = &tdq_groups[cpus]; /* * Setup a tdq group with one member. */ tdq->tdq_transferable = 0; tdq->tdq_group = tdg; tdg->tdg_cpus = 1; tdg->tdg_idlemask = 0; tdg->tdg_cpumask = tdg->tdg_mask = 1 << i; tdg->tdg_load = 0; tdg->tdg_transferable = 0; LIST_INIT(&tdg->tdg_members); LIST_INSERT_HEAD(&tdg->tdg_members, tdq, tdq_siblings); cpus++; } tdg_maxid = cpus - 1; } else { struct tdq_group *tdg; struct cpu_group *cg; int j; topology = 1; for (i = 0; i < smp_topology->ct_count; i++) { cg = &smp_topology->ct_group[i]; tdg = &tdq_groups[i]; /* * Initialize the group. */ tdg->tdg_idlemask = 0; tdg->tdg_load = 0; tdg->tdg_transferable = 0; tdg->tdg_cpus = cg->cg_count; tdg->tdg_cpumask = cg->cg_mask; LIST_INIT(&tdg->tdg_members); /* * Find all of the group members and add them. */ for (j = 0; j < MAXCPU; j++) { if ((cg->cg_mask & (1 << j)) != 0) { if (tdg->tdg_mask == 0) tdg->tdg_mask = 1 << j; tdq_cpu[j].tdq_transferable = 0; tdq_cpu[j].tdq_group = tdg; LIST_INSERT_HEAD(&tdg->tdg_members, &tdq_cpu[j], tdq_siblings); } } if (tdg->tdg_cpus > 1) balance_groups = 1; } tdg_maxid = smp_topology->ct_count - 1; } /* * Stagger the group and global load balancer so they do not * interfere with each other. */ bal_tick = ticks + hz; if (balance_groups) gbal_tick = ticks + (hz / 2); #else tdq_setup(TDQ_SELF()); #endif mtx_lock_spin(&sched_lock); tdq_load_add(TDQ_SELF(), &td_sched0); mtx_unlock_spin(&sched_lock); } /* ARGSUSED */ static void sched_initticks(void *dummy) { mtx_lock_spin(&sched_lock); realstathz = stathz ? stathz : hz; sched_slice = (realstathz/10); /* ~100ms */ /* * tickincr is shifted out by 10 to avoid rounding errors due to * hz not being evenly divisible by stathz on all platforms. */ tickincr = (hz << SCHED_TICK_SHIFT) / realstathz; /* * This does not work for values of stathz that are more than * 1 << SCHED_TICK_SHIFT * hz. In practice this does not happen. */ if (tickincr == 0) tickincr = 1; #ifdef SMP affinity = SCHED_AFFINITY_DEFAULT; #endif mtx_unlock_spin(&sched_lock); } /* * Scale the scheduling priority according to the "interactivity" of this * process. */ static void sched_priority(struct thread *td) { int score; int pri; if (td->td_pri_class != PRI_TIMESHARE) return; /* * If the score is interactive we place the thread in the realtime * queue with a priority that is less than kernel and interrupt * priorities. These threads are not subject to nice restrictions. * * Scores greater than this are placed on the normal realtime queue * where the priority is partially decided by the most recent cpu * utilization and the rest is decided by nice value. */ score = sched_interact_score(td); if (score < sched_interact) { pri = PRI_MIN_REALTIME; pri += ((PRI_MAX_REALTIME - PRI_MIN_REALTIME) / sched_interact) * score; KASSERT(pri >= PRI_MIN_REALTIME && pri <= PRI_MAX_REALTIME, ("sched_priority: invalid interactive priority %d score %d", pri, score)); } else { pri = SCHED_PRI_MIN; if (td->td_sched->ts_ticks) pri += SCHED_PRI_TICKS(td->td_sched); pri += SCHED_PRI_NICE(td->td_proc->p_nice); if (!(pri >= PRI_MIN_TIMESHARE && pri <= PRI_MAX_TIMESHARE)) { static int once = 1; if (once) { printf("sched_priority: invalid priority %d", pri); printf("nice %d, ticks %d ftick %d ltick %d tick pri %d\n", td->td_proc->p_nice, td->td_sched->ts_ticks, td->td_sched->ts_ftick, td->td_sched->ts_ltick, SCHED_PRI_TICKS(td->td_sched)); once = 0; } pri = min(max(pri, PRI_MIN_TIMESHARE), PRI_MAX_TIMESHARE); } } sched_user_prio(td, pri); return; } /* * This routine enforces a maximum limit on the amount of scheduling history * kept. It is called after either the slptime or runtime is adjusted. */ static void sched_interact_update(struct thread *td) { struct td_sched *ts; u_int sum; ts = td->td_sched; sum = ts->skg_runtime + ts->skg_slptime; if (sum < SCHED_SLP_RUN_MAX) return; /* * This only happens from two places: * 1) We have added an unusual amount of run time from fork_exit. * 2) We have added an unusual amount of sleep time from sched_sleep(). */ if (sum > SCHED_SLP_RUN_MAX * 2) { if (ts->skg_runtime > ts->skg_slptime) { ts->skg_runtime = SCHED_SLP_RUN_MAX; ts->skg_slptime = 1; } else { ts->skg_slptime = SCHED_SLP_RUN_MAX; ts->skg_runtime = 1; } return; } /* * If we have exceeded by more than 1/5th then the algorithm below * will not bring us back into range. Dividing by two here forces * us into the range of [4/5 * SCHED_INTERACT_MAX, SCHED_INTERACT_MAX] */ if (sum > (SCHED_SLP_RUN_MAX / 5) * 6) { ts->skg_runtime /= 2; ts->skg_slptime /= 2; return; } ts->skg_runtime = (ts->skg_runtime / 5) * 4; ts->skg_slptime = (ts->skg_slptime / 5) * 4; } static void sched_interact_fork(struct thread *td) { int ratio; int sum; sum = td->td_sched->skg_runtime + td->td_sched->skg_slptime; if (sum > SCHED_SLP_RUN_FORK) { ratio = sum / SCHED_SLP_RUN_FORK; td->td_sched->skg_runtime /= ratio; td->td_sched->skg_slptime /= ratio; } } static int sched_interact_score(struct thread *td) { int div; if (td->td_sched->skg_runtime > td->td_sched->skg_slptime) { div = max(1, td->td_sched->skg_runtime / SCHED_INTERACT_HALF); return (SCHED_INTERACT_HALF + (SCHED_INTERACT_HALF - (td->td_sched->skg_slptime / div))); } if (td->td_sched->skg_slptime > td->td_sched->skg_runtime) { div = max(1, td->td_sched->skg_slptime / SCHED_INTERACT_HALF); return (td->td_sched->skg_runtime / div); } /* runtime == slptime */ if (td->td_sched->skg_runtime) return (SCHED_INTERACT_HALF); /* * This can happen if slptime and runtime are 0. */ return (0); } /* * Called from proc0_init() to bootstrap the scheduler. */ void schedinit(void) { /* * Set up the scheduler specific parts of proc0. */ proc0.p_sched = NULL; /* XXX */ thread0.td_sched = &td_sched0; thread0.td_lock = &sched_lock; td_sched0.ts_ltick = ticks; td_sched0.ts_ftick = ticks; td_sched0.ts_thread = &thread0; } /* * This is only somewhat accurate since given many processes of the same * priority they will switch when their slices run out, which will be * at most sched_slice stathz ticks. */ int sched_rr_interval(void) { /* Convert sched_slice to hz */ return (hz/(realstathz/sched_slice)); } static void sched_pctcpu_update(struct td_sched *ts) { if (ts->ts_ticks == 0) return; if (ticks - (hz / 10) < ts->ts_ltick && SCHED_TICK_TOTAL(ts) < SCHED_TICK_MAX) return; /* * Adjust counters and watermark for pctcpu calc. */ if (ts->ts_ltick > ticks - SCHED_TICK_TARG) ts->ts_ticks = (ts->ts_ticks / (ticks - ts->ts_ftick)) * SCHED_TICK_TARG; else ts->ts_ticks = 0; ts->ts_ltick = ticks; ts->ts_ftick = ts->ts_ltick - SCHED_TICK_TARG; } static void sched_thread_priority(struct thread *td, u_char prio) { struct td_sched *ts; CTR6(KTR_SCHED, "sched_prio: %p(%s) prio %d newprio %d by %p(%s)", td, td->td_proc->p_comm, td->td_priority, prio, curthread, curthread->td_proc->p_comm); ts = td->td_sched; THREAD_LOCK_ASSERT(td, MA_OWNED); if (td->td_priority == prio) return; if (TD_ON_RUNQ(td) && prio < td->td_priority) { /* * If the priority has been elevated due to priority * propagation, we may have to move ourselves to a new * queue. This could be optimized to not re-add in some * cases. */ MPASS(td->td_lock == &sched_lock); sched_rem(td); td->td_priority = prio; sched_add(td, SRQ_BORROWING|SRQ_OURSELF); } else td->td_priority = prio; } /* * Update a thread's priority when it is lent another thread's * priority. */ void sched_lend_prio(struct thread *td, u_char prio) { td->td_flags |= TDF_BORROWING; sched_thread_priority(td, prio); } /* * Restore a thread's priority when priority propagation is * over. The prio argument is the minimum priority the thread * needs to have to satisfy other possible priority lending * requests. If the thread's regular priority is less * important than prio, the thread will keep a priority boost * of prio. */ void sched_unlend_prio(struct thread *td, u_char prio) { u_char base_pri; if (td->td_base_pri >= PRI_MIN_TIMESHARE && td->td_base_pri <= PRI_MAX_TIMESHARE) base_pri = td->td_user_pri; else base_pri = td->td_base_pri; if (prio >= base_pri) { td->td_flags &= ~TDF_BORROWING; sched_thread_priority(td, base_pri); } else sched_lend_prio(td, prio); } void sched_prio(struct thread *td, u_char prio) { u_char oldprio; /* First, update the base priority. */ td->td_base_pri = prio; /* * If the thread is borrowing another thread's priority, don't * ever lower the priority. */ if (td->td_flags & TDF_BORROWING && td->td_priority < prio) return; /* Change the real priority. */ oldprio = td->td_priority; sched_thread_priority(td, prio); /* * If the thread is on a turnstile, then let the turnstile update * its state. */ if (TD_ON_LOCK(td) && oldprio != prio) turnstile_adjust(td, oldprio); } void sched_user_prio(struct thread *td, u_char prio) { u_char oldprio; td->td_base_user_pri = prio; if (td->td_flags & TDF_UBORROWING && td->td_user_pri <= prio) return; oldprio = td->td_user_pri; td->td_user_pri = prio; if (TD_ON_UPILOCK(td) && oldprio != prio) umtx_pi_adjust(td, oldprio); } void sched_lend_user_prio(struct thread *td, u_char prio) { u_char oldprio; td->td_flags |= TDF_UBORROWING; oldprio = td->td_user_pri; td->td_user_pri = prio; if (TD_ON_UPILOCK(td) && oldprio != prio) umtx_pi_adjust(td, oldprio); } void sched_unlend_user_prio(struct thread *td, u_char prio) { u_char base_pri; base_pri = td->td_base_user_pri; if (prio >= base_pri) { td->td_flags &= ~TDF_UBORROWING; sched_user_prio(td, base_pri); } else sched_lend_user_prio(td, prio); } void sched_switch(struct thread *td, struct thread *newtd, int flags) { struct tdq *tdq; struct td_sched *ts; int preempt; THREAD_LOCK_ASSERT(td, MA_OWNED); preempt = flags & SW_PREEMPT; tdq = TDQ_SELF(); ts = td->td_sched; td->td_lastcpu = td->td_oncpu; td->td_oncpu = NOCPU; td->td_flags &= ~TDF_NEEDRESCHED; td->td_owepreempt = 0; /* * If the thread has been assigned it may be in the process of switching * to the new cpu. This is the case in sched_bind(). */ /* * Switch to the sched lock to fix things up and pick * a new thread. */ if (td->td_lock != &sched_lock) { mtx_lock_spin(&sched_lock); thread_unlock(td); } if (TD_IS_IDLETHREAD(td)) { MPASS(td->td_lock == &sched_lock); TD_SET_CAN_RUN(td); } else if (TD_IS_RUNNING(td)) { /* * Don't allow the thread to migrate * from a preemption. */ tdq_load_rem(tdq, ts); if (preempt) sched_pin_td(td); sched_add(td, preempt ? SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED : SRQ_OURSELF|SRQ_YIELDING); if (preempt) sched_unpin_td(td); } else tdq_load_rem(tdq, ts); mtx_assert(&sched_lock, MA_OWNED); if (newtd != NULL) { /* * If we bring in a thread account for it as if it had been * added to the run queue and then chosen. */ TD_SET_RUNNING(newtd); tdq_load_add(TDQ_SELF(), newtd->td_sched); } else newtd = choosethread(); if (td != newtd) { #ifdef HWPMC_HOOKS if (PMC_PROC_IS_USING_PMCS(td->td_proc)) PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT); #endif cpu_switch(td, newtd, td->td_lock); #ifdef HWPMC_HOOKS if (PMC_PROC_IS_USING_PMCS(td->td_proc)) PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN); #endif } sched_lock.mtx_lock = (uintptr_t)td; td->td_oncpu = PCPU_GET(cpuid); MPASS(td->td_lock == &sched_lock); } void sched_nice(struct proc *p, int nice) { struct thread *td; PROC_LOCK_ASSERT(p, MA_OWNED); PROC_SLOCK_ASSERT(p, MA_OWNED); p->p_nice = nice; FOREACH_THREAD_IN_PROC(p, td) { thread_lock(td); sched_priority(td); sched_prio(td, td->td_base_user_pri); thread_unlock(td); } } void sched_sleep(struct thread *td) { THREAD_LOCK_ASSERT(td, MA_OWNED); td->td_sched->ts_slptime = ticks; } void sched_wakeup(struct thread *td) { struct td_sched *ts; int slptime; THREAD_LOCK_ASSERT(td, MA_OWNED); ts = td->td_sched; /* * If we slept for more than a tick update our interactivity and * priority. */ slptime = ts->ts_slptime; ts->ts_slptime = 0; if (slptime && slptime != ticks) { u_int hzticks; hzticks = (ticks - slptime) << SCHED_TICK_SHIFT; ts->skg_slptime += hzticks; sched_interact_update(td); sched_pctcpu_update(ts); sched_priority(td); } /* Reset the slice value after we sleep. */ ts->ts_slice = sched_slice; sched_add(td, SRQ_BORING); } /* * Penalize the parent for creating a new child and initialize the child's * priority. */ void sched_fork(struct thread *td, struct thread *child) { THREAD_LOCK_ASSERT(td, MA_OWNED); sched_fork_thread(td, child); /* * Penalize the parent and child for forking. */ sched_interact_fork(child); sched_priority(child); td->td_sched->skg_runtime += tickincr; sched_interact_update(td); sched_priority(td); } void sched_fork_thread(struct thread *td, struct thread *child) { struct td_sched *ts; struct td_sched *ts2; /* * Initialize child. */ THREAD_LOCK_ASSERT(td, MA_OWNED); sched_newthread(child); child->td_lock = &sched_lock; ts = td->td_sched; ts2 = child->td_sched; ts2->ts_cpu = ts->ts_cpu; ts2->ts_runq = NULL; /* * Grab our parents cpu estimation information and priority. */ ts2->ts_ticks = ts->ts_ticks; ts2->ts_ltick = ts->ts_ltick; ts2->ts_ftick = ts->ts_ftick; child->td_user_pri = td->td_user_pri; child->td_base_user_pri = td->td_base_user_pri; /* * And update interactivity score. */ ts2->skg_slptime = ts->skg_slptime; ts2->skg_runtime = ts->skg_runtime; ts2->ts_slice = 1; /* Attempt to quickly learn interactivity. */ } void sched_class(struct thread *td, int class) { THREAD_LOCK_ASSERT(td, MA_OWNED); if (td->td_pri_class == class) return; #ifdef SMP /* * On SMP if we're on the RUNQ we must adjust the transferable * count because could be changing to or from an interrupt * class. */ if (TD_ON_RUNQ(td)) { struct tdq *tdq; tdq = TDQ_CPU(td->td_sched->ts_cpu); if (THREAD_CAN_MIGRATE(td)) { tdq->tdq_transferable--; tdq->tdq_group->tdg_transferable--; } td->td_pri_class = class; if (THREAD_CAN_MIGRATE(td)) { tdq->tdq_transferable++; tdq->tdq_group->tdg_transferable++; } } #endif td->td_pri_class = class; } /* * Return some of the child's priority and interactivity to the parent. */ void sched_exit(struct proc *p, struct thread *child) { struct thread *td; CTR3(KTR_SCHED, "sched_exit: %p(%s) prio %d", child, child->td_proc->p_comm, child->td_priority); PROC_SLOCK_ASSERT(p, MA_OWNED); td = FIRST_THREAD_IN_PROC(p); sched_exit_thread(td, child); } void sched_exit_thread(struct thread *td, struct thread *child) { CTR3(KTR_SCHED, "sched_exit_thread: %p(%s) prio %d", child, child->td_proc->p_comm, child->td_priority); thread_lock(child); tdq_load_rem(TDQ_CPU(child->td_sched->ts_cpu), child->td_sched); thread_unlock(child); #ifdef KSE /* * KSE forks and exits so often that this penalty causes short-lived * threads to always be non-interactive. This causes mozilla to * crawl under load. */ if ((td->td_pflags & TDP_SA) && td->td_proc == child->td_proc) return; #endif /* * Give the child's runtime to the parent without returning the * sleep time as a penalty to the parent. This causes shells that * launch expensive things to mark their children as expensive. */ thread_lock(td); td->td_sched->skg_runtime += child->td_sched->skg_runtime; sched_interact_update(td); sched_priority(td); thread_unlock(td); } void sched_userret(struct thread *td) { /* * XXX we cheat slightly on the locking here to avoid locking in * the usual case. Setting td_priority here is essentially an * incomplete workaround for not setting it properly elsewhere. * Now that some interrupt handlers are threads, not setting it * properly elsewhere can clobber it in the window between setting * it here and returning to user mode, so don't waste time setting * it perfectly here. */ KASSERT((td->td_flags & TDF_BORROWING) == 0, ("thread with borrowed priority returning to userland")); if (td->td_priority != td->td_user_pri) { thread_lock(td); td->td_priority = td->td_user_pri; td->td_base_pri = td->td_user_pri; thread_unlock(td); } } void sched_clock(struct thread *td) { struct tdq *tdq; struct td_sched *ts; mtx_assert(&sched_lock, MA_OWNED); #ifdef SMP sched_smp_tick(td); #endif tdq = TDQ_SELF(); /* * Advance the insert index once for each tick to ensure that all * threads get a chance to run. */ if (tdq->tdq_idx == tdq->tdq_ridx) { tdq->tdq_idx = (tdq->tdq_idx + 1) % RQ_NQS; if (TAILQ_EMPTY(&tdq->tdq_timeshare.rq_queues[tdq->tdq_ridx])) tdq->tdq_ridx = tdq->tdq_idx; } ts = td->td_sched; /* * We only do slicing code for TIMESHARE threads. */ if (td->td_pri_class != PRI_TIMESHARE) return; /* * We used a tick; charge it to the thread so that we can compute our * interactivity. */ td->td_sched->skg_runtime += tickincr; sched_interact_update(td); /* * We used up one time slice. */ if (--ts->ts_slice > 0) return; /* * We're out of time, recompute priorities and requeue. */ sched_priority(td); td->td_flags |= TDF_NEEDRESCHED; } int sched_runnable(void) { struct tdq *tdq; int load; load = 1; tdq = TDQ_SELF(); #ifdef SMP if (tdq_busy) goto out; #endif if ((curthread->td_flags & TDF_IDLETD) != 0) { if (tdq->tdq_load > 0) goto out; } else if (tdq->tdq_load - 1 > 0) goto out; load = 0; out: return (load); } struct thread * sched_choose(void) { struct tdq *tdq; struct td_sched *ts; mtx_assert(&sched_lock, MA_OWNED); tdq = TDQ_SELF(); #ifdef SMP restart: #endif ts = tdq_choose(tdq); if (ts) { #ifdef SMP if (ts->ts_thread->td_priority > PRI_MIN_IDLE) if (tdq_idled(tdq) == 0) goto restart; #endif tdq_runq_rem(tdq, ts); return (ts->ts_thread); } #ifdef SMP if (tdq_idled(tdq) == 0) goto restart; #endif return (PCPU_GET(idlethread)); } static int sched_preempt(struct thread *td) { struct thread *ctd; int cpri; int pri; ctd = curthread; pri = td->td_priority; cpri = ctd->td_priority; if (panicstr != NULL || pri >= cpri || cold || TD_IS_INHIBITED(ctd)) return (0); /* * Always preempt IDLE threads. Otherwise only if the preempting * thread is an ithread. */ if (pri > PRI_MAX_ITHD && cpri < PRI_MIN_IDLE) return (0); if (ctd->td_critnest > 1) { CTR1(KTR_PROC, "sched_preempt: in critical section %d", ctd->td_critnest); ctd->td_owepreempt = 1; return (0); } /* * Thread is runnable but not yet put on system run queue. */ MPASS(TD_ON_RUNQ(td)); TD_SET_RUNNING(td); MPASS(ctd->td_lock == &sched_lock); MPASS(td->td_lock == &sched_lock); CTR3(KTR_PROC, "preempting to thread %p (pid %d, %s)\n", td, td->td_proc->p_pid, td->td_proc->p_comm); /* * We enter the switch with two runnable threads that both have * the same lock. When we return td may be sleeping so we need * to switch locks to make sure he's locked correctly. */ SCHED_STAT_INC(switch_preempt); mi_switch(SW_INVOL|SW_PREEMPT, td); spinlock_enter(); thread_unlock(ctd); thread_lock(td); spinlock_exit(); return (1); } void sched_add(struct thread *td, int flags) { struct tdq *tdq; struct td_sched *ts; int preemptive; int class; #ifdef SMP int cpuid; int cpumask; #endif ts = td->td_sched; THREAD_LOCK_ASSERT(td, MA_OWNED); CTR5(KTR_SCHED, "sched_add: %p(%s) prio %d by %p(%s)", td, td->td_proc->p_comm, td->td_priority, curthread, curthread->td_proc->p_comm); KASSERT((td->td_inhibitors == 0), ("sched_add: trying to run inhibited thread")); KASSERT((TD_CAN_RUN(td) || TD_IS_RUNNING(td)), ("sched_add: bad thread state")); KASSERT(td->td_proc->p_sflag & PS_INMEM, ("sched_add: process swapped out")); /* * Now that the thread is moving to the run-queue, set the lock * to the scheduler's lock. */ if (td->td_lock != &sched_lock) { mtx_lock_spin(&sched_lock); thread_lock_set(td, &sched_lock); } mtx_assert(&sched_lock, MA_OWNED); TD_SET_RUNQ(td); tdq = TDQ_SELF(); class = PRI_BASE(td->td_pri_class); preemptive = !(flags & SRQ_YIELDING); /* * Recalculate the priority before we select the target cpu or * run-queue. */ if (class == PRI_TIMESHARE) sched_priority(td); if (ts->ts_slice == 0) ts->ts_slice = sched_slice; #ifdef SMP cpuid = PCPU_GET(cpuid); /* * Pick the destination cpu and if it isn't ours transfer to the * target cpu. */ if (THREAD_CAN_MIGRATE(td)) { if (td->td_priority <= PRI_MAX_ITHD) { CTR2(KTR_ULE, "ithd %d < %d", td->td_priority, PRI_MAX_ITHD); ts->ts_cpu = cpuid; } else if (pick_pri) ts->ts_cpu = tdq_pickpri(tdq, ts, flags); else ts->ts_cpu = tdq_pickidle(tdq, ts); } else CTR1(KTR_ULE, "pinned %d", td->td_pinned); if (ts->ts_cpu != cpuid) preemptive = 0; tdq = TDQ_CPU(ts->ts_cpu); cpumask = 1 << ts->ts_cpu; /* * If we had been idle, clear our bit in the group and potentially * the global bitmap. */ if ((class != PRI_IDLE && class != PRI_ITHD) && (tdq->tdq_group->tdg_idlemask & cpumask) != 0) { /* * Check to see if our group is unidling, and if so, remove it * from the global idle mask. */ if (tdq->tdq_group->tdg_idlemask == tdq->tdq_group->tdg_cpumask) atomic_clear_int(&tdq_idle, tdq->tdq_group->tdg_mask); /* * Now remove ourselves from the group specific idle mask. */ tdq->tdq_group->tdg_idlemask &= ~cpumask; } #endif /* * Pick the run queue based on priority. */ if (td->td_priority <= PRI_MAX_REALTIME) ts->ts_runq = &tdq->tdq_realtime; else if (td->td_priority <= PRI_MAX_TIMESHARE) ts->ts_runq = &tdq->tdq_timeshare; else ts->ts_runq = &tdq->tdq_idle; if (preemptive && sched_preempt(td)) return; tdq_runq_add(tdq, ts, flags); tdq_load_add(tdq, ts); #ifdef SMP if (ts->ts_cpu != cpuid) { tdq_notify(ts); return; } #endif if (td->td_priority < curthread->td_priority) curthread->td_flags |= TDF_NEEDRESCHED; } void sched_rem(struct thread *td) { struct tdq *tdq; struct td_sched *ts; CTR5(KTR_SCHED, "sched_rem: %p(%s) prio %d by %p(%s)", td, td->td_proc->p_comm, td->td_priority, curthread, curthread->td_proc->p_comm); THREAD_LOCK_ASSERT(td, MA_OWNED); ts = td->td_sched; KASSERT(TD_ON_RUNQ(td), ("sched_rem: thread not on run queue")); tdq = TDQ_CPU(ts->ts_cpu); tdq_runq_rem(tdq, ts); tdq_load_rem(tdq, ts); TD_SET_CAN_RUN(td); } fixpt_t sched_pctcpu(struct thread *td) { fixpt_t pctcpu; struct td_sched *ts; pctcpu = 0; ts = td->td_sched; if (ts == NULL) return (0); thread_lock(td); if (ts->ts_ticks) { int rtick; sched_pctcpu_update(ts); /* How many rtick per second ? */ rtick = min(SCHED_TICK_HZ(ts) / SCHED_TICK_SECS, hz); pctcpu = (FSCALE * ((FSCALE * rtick)/hz)) >> FSHIFT; } td->td_proc->p_swtime = ts->ts_ltick - ts->ts_ftick; thread_unlock(td); return (pctcpu); } void sched_bind(struct thread *td, int cpu) { struct td_sched *ts; THREAD_LOCK_ASSERT(td, MA_OWNED); ts = td->td_sched; if (ts->ts_flags & TSF_BOUND) sched_unbind(td); ts->ts_flags |= TSF_BOUND; #ifdef SMP sched_pin(); if (PCPU_GET(cpuid) == cpu) return; ts->ts_cpu = cpu; /* When we return from mi_switch we'll be on the correct cpu. */ mi_switch(SW_VOL, NULL); #endif } void sched_unbind(struct thread *td) { struct td_sched *ts; THREAD_LOCK_ASSERT(td, MA_OWNED); ts = td->td_sched; if ((ts->ts_flags & TSF_BOUND) == 0) return; ts->ts_flags &= ~TSF_BOUND; #ifdef SMP sched_unpin(); #endif } int sched_is_bound(struct thread *td) { THREAD_LOCK_ASSERT(td, MA_OWNED); return (td->td_sched->ts_flags & TSF_BOUND); } void sched_relinquish(struct thread *td) { thread_lock(td); if (td->td_pri_class == PRI_TIMESHARE) sched_prio(td, PRI_MAX_TIMESHARE); SCHED_STAT_INC(switch_relinquish); mi_switch(SW_VOL, NULL); thread_unlock(td); } int sched_load(void) { #ifdef SMP int total; int i; total = 0; for (i = 0; i <= tdg_maxid; i++) total += TDQ_GROUP(i)->tdg_load; return (total); #else return (TDQ_SELF()->tdq_sysload); #endif } int sched_sizeof_proc(void) { return (sizeof(struct proc)); } int sched_sizeof_thread(void) { return (sizeof(struct thread) + sizeof(struct td_sched)); } void sched_tick(void) { struct td_sched *ts; ts = curthread->td_sched; /* Adjust ticks for pctcpu */ ts->ts_ticks += 1 << SCHED_TICK_SHIFT; ts->ts_ltick = ticks; /* * Update if we've exceeded our desired tick threshhold by over one * second. */ if (ts->ts_ftick + SCHED_TICK_MAX < ts->ts_ltick) sched_pctcpu_update(ts); } /* * The actual idle process. */ void sched_idletd(void *dummy) { struct proc *p; struct thread *td; td = curthread; p = td->td_proc; mtx_assert(&Giant, MA_NOTOWNED); /* ULE Relies on preemption for idle interruption. */ for (;;) cpu_idle(); } /* * A CPU is entering for the first time or a thread is exiting. */ void sched_throw(struct thread *td) { /* * Correct spinlock nesting. The idle thread context that we are * borrowing was created so that it would start out with a single * spin lock (sched_lock) held in fork_trampoline(). Since we've * explicitly acquired locks in this function, the nesting count * is now 2 rather than 1. Since we are nested, calling * spinlock_exit() will simply adjust the counts without allowing * spin lock using code to interrupt us. */ if (td == NULL) { mtx_lock_spin(&sched_lock); spinlock_exit(); } else { MPASS(td->td_lock == &sched_lock); } mtx_assert(&sched_lock, MA_OWNED); KASSERT(curthread->td_md.md_spinlock_count == 1, ("invalid count")); PCPU_SET(switchtime, cpu_ticks()); PCPU_SET(switchticks, ticks); cpu_throw(td, choosethread()); /* doesn't return */ } void sched_fork_exit(struct thread *ctd) { struct thread *td; /* * Finish setting up thread glue so that it begins execution in a * non-nested critical section with sched_lock held but not recursed. */ ctd->td_oncpu = PCPU_GET(cpuid); sched_lock.mtx_lock = (uintptr_t)ctd; THREAD_LOCK_ASSERT(ctd, MA_OWNED | MA_NOTRECURSED); /* * Processes normally resume in mi_switch() after being * cpu_switch()'ed to, but when children start up they arrive here * instead, so we must do much the same things as mi_switch() would. */ if ((td = PCPU_GET(deadthread))) { PCPU_SET(deadthread, NULL); thread_stash(td); } thread_unlock(ctd); } static SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0, "Scheduler"); SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "ule", 0, "Scheduler name"); SYSCTL_INT(_kern_sched, OID_AUTO, slice, CTLFLAG_RW, &sched_slice, 0, ""); SYSCTL_INT(_kern_sched, OID_AUTO, interact, CTLFLAG_RW, &sched_interact, 0, ""); SYSCTL_INT(_kern_sched, OID_AUTO, tickincr, CTLFLAG_RD, &tickincr, 0, ""); SYSCTL_INT(_kern_sched, OID_AUTO, realstathz, CTLFLAG_RD, &realstathz, 0, ""); #ifdef SMP SYSCTL_INT(_kern_sched, OID_AUTO, pick_pri, CTLFLAG_RW, &pick_pri, 0, ""); SYSCTL_INT(_kern_sched, OID_AUTO, pick_pri_affinity, CTLFLAG_RW, &affinity, 0, ""); SYSCTL_INT(_kern_sched, OID_AUTO, pick_pri_tryself, CTLFLAG_RW, &tryself, 0, ""); SYSCTL_INT(_kern_sched, OID_AUTO, pick_pri_tryselfidle, CTLFLAG_RW, &tryselfidle, 0, ""); SYSCTL_INT(_kern_sched, OID_AUTO, balance, CTLFLAG_RW, &rebalance, 0, ""); SYSCTL_INT(_kern_sched, OID_AUTO, ipi_preempt, CTLFLAG_RW, &ipi_preempt, 0, ""); SYSCTL_INT(_kern_sched, OID_AUTO, ipi_ast, CTLFLAG_RW, &ipi_ast, 0, ""); SYSCTL_INT(_kern_sched, OID_AUTO, ipi_thresh, CTLFLAG_RW, &ipi_thresh, 0, ""); SYSCTL_INT(_kern_sched, OID_AUTO, steal_htt, CTLFLAG_RW, &steal_htt, 0, ""); SYSCTL_INT(_kern_sched, OID_AUTO, steal_busy, CTLFLAG_RW, &steal_busy, 0, ""); SYSCTL_INT(_kern_sched, OID_AUTO, busy_thresh, CTLFLAG_RW, &busy_thresh, 0, ""); SYSCTL_INT(_kern_sched, OID_AUTO, topology, CTLFLAG_RD, &topology, 0, ""); #endif /* ps compat */ static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */ SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, ""); #define KERN_SWITCH_INCLUDE 1 #include "kern/kern_switch.c"