/*- * 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: src/sys/kern/sched_ule.c,v 1.192 2007/04/20 05:45:46 kmacy Exp $"); #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 0 /* * 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) #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. * preempt_thresh: Priority threshold for preemption and remote IPIs. */ static int sched_interact = SCHED_INTERACT_THRESH; static int realstathz; static int tickincr; static int sched_slice; static int preempt_thresh = PRI_MIN_KERN; #define SCHED_BAL_SECS 2 /* How often we run the rebalance algorithm. */ /* * tdq - per processor runqs and statistics. */ struct tdq { struct mtx tdq_lock; /* Protects all fields below. */ struct runq tdq_idle; /* Queue of IDLE threads. */ struct runq tdq_timeshare; /* timeshare run queue. */ struct runq tdq_realtime; /* real-time run queue. */ int tdq_load; /* Aggregate load. */ u_char tdq_idx; /* Current insert index. */ u_char tdq_ridx; /* Current removal index. */ #ifdef SMP u_char tdq_lowpri; /* Lowest priority thread */ 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 char tdq_name[32]; /* lock name */ char tdq_runname[32]; /* run lock name */ /* * tdq_runlock is purposefully placed where it will be in it's own * cacheline. */ struct mtx tdq_runlock; /* Protects running thread. */ } __aligned(64); #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. */ } __aligned(64); #define SCHED_AFFINITY_DEFAULT (max(1, hz / 300)) #define SCHED_AFFINITY(ts) ((ts)->ts_rltick > ticks - affinity) /* * Run-time tunables. */ static int rebalance = 0; static int pick_pri = 0; static int pick_mysql = 0; static int affinity; static int tryself = 1; static int tryselfidle = 1; static int steal_htt = 0; static int steal_busy = 0; static int topology = 0; /* * One thread queue per processor. */ static volatile cpumask_t tdq_idle; 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 #define TDQ_LOCK_ASSERT(t, type) mtx_assert(TDQ_LOCKPTR((t)), (type)) #define TDQ_LOCK(t) mtx_lock_spin(TDQ_LOCKPTR((t))) #define TDQ_LOCK_FLAGS(t, f) mtx_lock_spin_flags(TDQ_LOCKPTR((t)), (f)) #define TDQ_UNLOCK(t) mtx_unlock_spin(TDQ_LOCKPTR((t))) #define TDQ_LOCKPTR(t) (&(t)->tdq_lock) #define TDQ_RUN_LOCK_ASSERT(t, type) mtx_assert(TDQ_RUN_LOCKPTR((t)), (type)) #define TDQ_RUN_LOCK(t) mtx_lock_spin(TDQ_RUN_LOCKPTR((t))) #define TDQ_RUN_LOCK_FLAGS(t, f) mtx_lock_spin_flags(TDQ_RUN_LOCKPTR((t)), (f)) #define TDQ_RUN_UNLOCK(t) mtx_unlock_spin(TDQ_RUN_LOCKPTR((t))) #define TDQ_RUN_LOCKPTR(t) (&(t)->tdq_runlock) 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 *); /* 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); static void tdq_add(struct tdq *, struct thread *, int); #ifdef SMP static int tdq_pickcpu(struct td_sched *, int); static void tdq_move(struct tdq *, struct tdq *); static int tdq_idled(struct tdq *); static void tdq_notify(struct td_sched *); static struct td_sched *tdq_steal(struct tdq *, 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(void); static inline struct mtx *thread_block_switch(struct thread *); static inline void thread_unblock_switch(struct thread *, struct mtx *); #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 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("\tlockptr %p\n", TDQ_LOCKPTR(tdq)); printf("\trun lockptr %p\n", TDQ_RUN_LOCKPTR(tdq)); printf("\tlock name %s\n", tdq->tdq_name); printf("\trun lock name %s\n", tdq->tdq_name); 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); printf("\tlowest priority: %d\n", tdq->tdq_lowpri); #endif } static __inline void tdq_runq_add(struct tdq *tdq, struct td_sched *ts, int flags) { TDQ_LOCK_ASSERT(tdq, MA_OWNED); THREAD_LOCK_ASSERT(ts->ts_thread, MA_OWNED); #ifdef SMP if (THREAD_CAN_MIGRATE(ts->ts_thread)) { tdq->tdq_transferable++; tdq->tdq_group->tdg_transferable++; ts->ts_flags |= TSF_XFERABLE; } #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) { TDQ_LOCK_ASSERT(tdq, MA_OWNED); KASSERT(ts->ts_runq != NULL, ("tdq_runq_remove: thread %p null ts_runq", ts->ts_thread)); #ifdef SMP if (ts->ts_flags & TSF_XFERABLE) { tdq->tdq_transferable--; tdq->tdq_group->tdg_transferable--; ts->ts_flags &= ~TSF_XFERABLE; } #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; TDQ_LOCK_ASSERT(tdq, MA_OWNED); THREAD_LOCK_ASSERT(ts->ts_thread, 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; THREAD_LOCK_ASSERT(ts->ts_thread, MA_OWNED); TDQ_LOCK_ASSERT(tdq, 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 KASSERT(tdq->tdq_load != 0, ("tdq_load_rem: Removing with 0 load on queue %jd", TDQ_ID(tdq))); tdq->tdq_load--; CTR1(KTR_SCHED, "load: %d", tdq->tdq_load); ts->ts_runq = NULL; } #ifdef SMP static void sched_smp_tick() { if (rebalance) { if (ticks >= bal_tick) sched_balance(); if (ticks >= gbal_tick && balance_groups) sched_balance_groups(); } } /* * 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 * simplicity and more gradual effects on load in larger systems. * */ 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 * SCHED_BAL_SECS)); 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 * SCHED_BAL_SECS)); 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 tdq_lock_pair(struct tdq *one, struct tdq *two) { if (one < two) { TDQ_LOCK(one); TDQ_LOCK_FLAGS(two, MTX_DUPOK); } else { TDQ_LOCK(two); TDQ_LOCK_FLAGS(one, MTX_DUPOK); } } 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; tdq_lock_pair(high, low); /* * 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; } /* * Determine what the imbalance is and then adjust that to how many * threads we actually have to give up (transferable). */ if (transferable != 0) { 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, low); } TDQ_UNLOCK(high); TDQ_UNLOCK(low); return; } static void tdq_move(struct tdq *from, struct tdq *to) { struct td_sched *ts; struct tdq *tdq; int cpu; tdq = from; cpu = TDQ_ID(to); 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) return; } if (tdq == to) return; sched_rem(ts->ts_thread); ts->ts_cpu = cpu; ts->ts_thread->td_lock = TDQ_LOCKPTR(to); tdq_add(to, ts->ts_thread, SRQ_YIELDING); } static int tdq_idled(struct tdq *tdq) { struct tdq_group *tdg; struct tdq *steal; struct td_sched *ts; struct thread *td; int highload; int highcpu; int load; int cpu; /* We don't want to be preempted while we're iterating over tdqs */ spinlock_enter(); 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; TDQ_LOCK(steal); ts = tdq_steal(steal, 0); if (ts) goto steal; TDQ_UNLOCK(steal); } } for (;;) { if (steal_busy == 0) break; highcpu = 0; highload = 0; for (cpu = 0; cpu <= mp_maxid; cpu++) { if (CPU_ABSENT(cpu)) continue; steal = TDQ_CPU(cpu); load = TDQ_CPU(cpu)->tdq_transferable; if (load < highload) continue; highload = load; highcpu = cpu; } if (highload < 2) break; steal = TDQ_CPU(highcpu); TDQ_LOCK(steal); if (steal->tdq_transferable > 1 && (ts = tdq_steal(steal, 1)) != NULL) goto steal; TDQ_UNLOCK(steal); break; } spinlock_exit(); return (1); steal: td = ts->ts_thread; thread_lock(td); spinlock_exit(); MPASS(td->td_lock == TDQ_LOCKPTR(steal)); TDQ_UNLOCK(steal); sched_rem(td); ts->ts_cpu = PCPU_GET(cpuid); thread_lock_block(td); TDQ_LOCK(tdq); thread_lock_unblock(td, TDQ_LOCKPTR(tdq)); tdq_add(tdq, td, SRQ_YIELDING); thread_lock(curthread); thread_unlock(td); mi_switch(SW_VOL, NULL); thread_unlock(curthread); 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 > preempt_thresh) return; sendipi: ctd->td_flags |= TDF_NEEDRESCHED; ipi_selected(1 << cpu, IPI_PREEMPT); } static struct td_sched * runq_steal_from(struct runq *rq, u_char start) { struct td_sched *ts; struct rqbits *rqb; struct rqhead *rqh; int first; int bit; int pri; int i; rqb = &rq->rq_status; bit = start & (RQB_BPW -1); pri = 0; first = 0; again: for (i = RQB_WORD(start); i < RQB_LEN; bit = 0, i++) { if (rqb->rqb_bits[i] == 0) continue; if (bit != 0) { for (pri = bit; pri < RQB_BPW; pri++) if (rqb->rqb_bits[i] & (1ul << pri)) break; if (pri >= RQB_BPW) continue; } else pri = RQB_FFS(rqb->rqb_bits[i]); pri += (i << RQB_L2BPW); rqh = &rq->rq_queues[pri]; TAILQ_FOREACH(ts, rqh, ts_procq) { if (first && THREAD_CAN_MIGRATE(ts->ts_thread)) return (ts); first = 1; } } if (start != 0) { start = 0; goto again; } return (NULL); } static struct td_sched * runq_steal(struct runq *rq) { struct rqhead *rqh; struct rqbits *rqb; struct td_sched *ts; int first; int word; int bit; first = 0; 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 (first && THREAD_CAN_MIGRATE(ts->ts_thread)) return (ts); first = 1; } } } return (NULL); } static struct td_sched * tdq_steal(struct tdq *tdq, int stealidle) { struct td_sched *ts; TDQ_LOCK_ASSERT(tdq, MA_OWNED); /* * 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_from(&tdq->tdq_timeshare, tdq->tdq_ridx)) != NULL) return (ts); if (stealidle) return (runq_steal(&tdq->tdq_idle)); return (NULL); } static inline struct tdq * sched_setcpu(struct td_sched *ts, int cpu, int flags) { struct thread *td; struct tdq *tdq; int self; THREAD_LOCK_ASSERT(ts->ts_thread, MA_OWNED); tdq = TDQ_CPU(cpu); td = ts->ts_thread; if (td->td_lock == TDQ_LOCKPTR(tdq)) goto setcpu; #ifdef notyet /* * If the thread isn't running it's lockptr is a * turnstile or a sleepqueue. We can just lock_set without * blocking. */ if (TD_CAN_RUN(td)) { TDQ_LOCK(tdq); thread_lock_set(td, TDQ_LOCKPTR(tdq)); goto setcpu; } #endif /* * This is via sched_switch(). We want to lock the tdq but leave * the thread blocked. We also have to unlock the current cpu's lock * if we're migrating. */ if (flags & SRQ_OURSELF) { self = PCPU_GET(cpuid); if (cpu == self) goto setcpu; MPASS(td->td_lock == &blocked_lock); TDQ_UNLOCK(TDQ_CPU(self)); TDQ_LOCK(tdq); goto setcpu; } /* * The hard case, migration, we need to block the thread first to * prevent order reversals with other cpus locks. */ thread_lock_block(td); TDQ_LOCK(tdq); thread_lock_unblock(td, TDQ_LOCKPTR(tdq)); setcpu: ts->ts_cpu = cpu; return (tdq); } static int tdq_lowestpri(void) { struct tdq *tdq; int lowpri; int lowcpu; int lowload; int load; int cpu; int pri; lowload = 0; lowpri = lowcpu = 0; for (cpu = 0; cpu <= mp_maxid; cpu++) { if (CPU_ABSENT(cpu)) continue; tdq = TDQ_CPU(cpu); pri = tdq->tdq_lowpri; load = TDQ_CPU(cpu)->tdq_load; CTR4(KTR_ULE, "cpu %d pri %d lowcpu %d lowpri %d", cpu, pri, lowcpu, lowpri); if (pri < lowpri) continue; if (lowpri && lowpri == pri && load > lowload) continue; lowpri = pri; lowcpu = cpu; lowload = load; } return (lowcpu); } static int tdq_lowestload(void) { struct tdq *tdq; int lowload; int lowpri; int lowcpu; int load; int cpu; int pri; lowcpu = 0; lowload = TDQ_CPU(0)->tdq_load; lowpri = TDQ_CPU(0)->tdq_lowpri; for (cpu = 1; cpu <= mp_maxid; cpu++) { if (CPU_ABSENT(cpu)) continue; tdq = TDQ_CPU(cpu); load = tdq->tdq_load; pri = tdq->tdq_lowpri; CTR4(KTR_ULE, "cpu %d load %d lowcpu %d lowload %d", cpu, load, lowcpu, lowload); if (load > lowload) continue; if (load == lowload && pri < lowpri) continue; lowcpu = cpu; lowload = load; lowpri = pri; } return (lowcpu); } static int tdq_pickcpu(struct td_sched *ts, int flags) { struct tdq *tdq; int self; int pri; int cpu; cpu = self = PCPU_GET(cpuid); if (smp_started == 0) return (self); pri = ts->ts_thread->td_priority; cpu = ts->ts_cpu; /* * Regardless of affinity, if the last cpu is idle send it there. */ tdq = TDQ_CPU(cpu); if (tdq->tdq_lowpri > 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, tdq->tdq_lowpri); return (ts->ts_cpu); } /* * If we have affinity, try to place it on the cpu we last ran on. */ if (SCHED_AFFINITY(ts) && tdq->tdq_lowpri > pri) { CTR5(KTR_ULE, "affinity for %d, ltick %d ticks %d pri %d curthread %d", ts->ts_cpu, ts->ts_rltick, ticks, pri, tdq->tdq_lowpri); 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); if (tryselfidle && pri < curthread->td_priority) { CTR1(KTR_ULE, "tryselfidle %d", curthread->td_priority); return (self); } /* * XXX Under heavy load mysql performs way better if you * serialize the non-running threads on one cpu. This is * a horrible hack. */ if (pick_mysql) return (0); /* * Now search for the cpu running the lowest priority thread with * the least load. */ if (pick_pri) cpu = tdq_lowestpri(); else cpu = tdq_lowestload(); return (cpu); } #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; TDQ_LOCK_ASSERT(tdq, MA_OWNED); ts = runq_choose(&tdq->tdq_realtime); if (ts != NULL) return (ts); ts = runq_choose_from(&tdq->tdq_timeshare, tdq->tdq_ridx); if (ts != NULL) { KASSERT(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) { snprintf(tdq->tdq_name, sizeof(tdq->tdq_name), "sched queue lock %d", (int)TDQ_ID(tdq)); snprintf(tdq->tdq_runname, sizeof(tdq->tdq_name), "sched run lock %d", (int)TDQ_ID(tdq)); mtx_init(&tdq->tdq_lock, tdq->tdq_name, "sched lock", MTX_SPIN | MTX_RECURSE); mtx_init(&tdq->tdq_runlock, tdq->tdq_runname, "sched run lock", MTX_SPIN | MTX_RECURSE); 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) { struct tdq *tdq; #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++) { tdq = &tdq_cpu[i]; tdq_setup(&tdq_cpu[i]); } if (smp_topology == NULL) { struct tdq_group *tdg; 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 tdq = TDQ_SELF(); TDQ_LOCK(tdq); tdq_load_add(tdq, &td_sched0); TDQ_UNLOCK(tdq); } /* ARGSUSED */ static void sched_initticks(void *dummy) { int incr; 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. */ incr = (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 (incr == 0) incr = 1; tickincr = incr; #ifdef SMP affinity = SCHED_AFFINITY_DEFAULT; #endif } static int sched_interact_score(struct thread *td) { struct td_sched *ts; int div; ts = td->td_sched; /* * The score is only needed if this is likely to be an interactive * task. Don't go through the expense of computing it if there's * no chance. */ if (sched_interact <= SCHED_INTERACT_HALF && ts->skg_runtime >= ts->skg_slptime) return (SCHED_INTERACT_HALF); if (ts->skg_runtime > ts->skg_slptime) { div = max(1, ts->skg_runtime / SCHED_INTERACT_HALF); return (SCHED_INTERACT_HALF + (SCHED_INTERACT_HALF - (ts->skg_slptime / div))); } if (ts->skg_slptime > ts->skg_runtime) { div = max(1, ts->skg_slptime / SCHED_INTERACT_HALF); return (ts->skg_runtime / div); } /* runtime == slptime */ if (ts->skg_runtime) return (SCHED_INTERACT_HALF); /* * This can happen if slptime and runtime are 0. */ return (0); } /* * 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); KASSERT(pri >= PRI_MIN_TIMESHARE && pri <= PRI_MAX_TIMESHARE, ("sched_priority: invalid priority %d: nice %d, " "ticks %d ftick %d ltick %d tick pri %d", pri, 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))); } 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; } } /* * 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 = TDQ_LOCKPTR(TDQ_SELF()); 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. */ sched_rem(td); td->td_priority = prio; sched_add(td, SRQ_BORROWING); } else { #ifdef SMP struct tdq *tdq; tdq = TDQ_CPU(ts->ts_cpu); if (prio < tdq->tdq_lowpri) tdq->tdq_lowpri = prio; #endif 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); } static inline struct mtx * thread_block_switch(struct thread *td) { struct mtx *lock; THREAD_LOCK_ASSERT(td, MA_OWNED); lock = td->td_lock; td->td_lock = &blocked_lock; mtx_unlock_spin(lock); return (lock); } static inline void thread_unblock_switch(struct thread *td, struct mtx *mtx) { atomic_store_rel_ptr((volatile uintptr_t *)&td->td_lock, (uintptr_t)mtx); } void sched_switch(struct thread *td, struct thread *newtd, int flags) { struct tdq *tdq; struct td_sched *ts; struct mtx *mtx; int cpuid; THREAD_LOCK_ASSERT(td, MA_OWNED); cpuid = PCPU_GET(cpuid); tdq = TDQ_CPU(cpuid); ts = td->td_sched; #ifdef SMP ts->ts_rltick = ticks; #endif td->td_lastcpu = td->td_oncpu; td->td_oncpu = NOCPU; td->td_flags &= ~TDF_NEEDRESCHED; td->td_owepreempt = 0; /* * Block the thread so we're free to acquire the correct run queue * locks. */ mtx = thread_lock_block(td); /* * If we've been given a thread to execute just add it to the * run queue rather than directly dispatching. Only KSE does this * now. This must happen while curthread is blocked. */ if (newtd != NULL) { thread_lock(newtd); sched_add(newtd, SRQ_YIELDING); thread_unlock(newtd); } TDQ_LOCK(tdq); /* * Take care of the outgoing thread's state. */ if (TD_IS_IDLETHREAD(td)) { TD_SET_CAN_RUN(td); mtx = TDQ_LOCKPTR(tdq); } else if (TD_IS_RUNNING(td)) { tdq_load_rem(tdq, ts); sched_add(td, (flags & SW_PREEMPT) ? SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED : SRQ_OURSELF|SRQ_YIELDING); /* mtx is no longer the running lock */ mtx = TDQ_LOCKPTR(TDQ_CPU(ts->ts_cpu)); /* * If we migrated in sched_add our lock was dropped and the * new one was picked up in sched_setcpu(). */ if (ts->ts_cpu != cpuid) { mtx_unlock_spin(mtx); TDQ_LOCK(tdq); } } else tdq_load_rem(tdq, ts); /* Drop the extra spinlock nesting acquired in thread_lock_block */ spinlock_exit(); TDQ_LOCK_ASSERT(tdq, MA_OWNED | MA_NOTRECURSED); /* * Now that we've taken care of the outgoing thread pick a new one * and switch while we hold the tdq lock. */ 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, mtx); /* * We may return from cpu_switch on a different cpu. However, * we always return with td_lock pointing to the current cpu's * run queue lock. */ cpuid = PCPU_GET(cpuid); tdq = TDQ_CPU(cpuid); TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)td; #ifdef HWPMC_HOOKS if (PMC_PROC_IS_USING_PMCS(td->td_proc)) PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_IN); #endif } else thread_unblock_switch(td, mtx); #ifdef SMP /* We should always get here with the lowest priority td possible */ tdq->tdq_lowpri = td->td_priority; #endif TDQ_LOCK_ASSERT(tdq, MA_OWNED|MA_NOTRECURSED); MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); /* * Switch is complete; transition to the run lock to reduce * contention on the runqueue lock. */ TDQ_RUN_LOCK(tdq); thread_lock_set(td, TDQ_RUN_LOCKPTR(tdq)); td->td_oncpu = cpuid; } 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 = TDQ_LOCKPTR(TDQ_SELF()); 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); #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; THREAD_LOCK_ASSERT(td, MA_OWNED); 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(); 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) { #ifdef SMP struct tdq_group *tdg; #endif struct td_sched *ts; struct tdq *tdq; tdq = TDQ_SELF(); TDQ_LOCK_ASSERT(tdq, MA_OWNED); ts = tdq_choose(tdq); if (ts) { tdq_runq_rem(tdq, ts); return (ts->ts_thread); } #ifdef SMP /* * 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 = tdq->tdq_group; tdg->tdg_idlemask |= PCPU_GET(cpumask); if (tdg->tdg_idlemask == tdg->tdg_cpumask) atomic_set_int(&tdq_idle, tdg->tdg_mask); #endif return (PCPU_GET(idlethread)); } static inline void sched_setpreempt(struct thread *td) { struct thread *ctd; int cpri; int pri; ctd = curthread; pri = td->td_priority; cpri = ctd->td_priority; if (td->td_priority < ctd->td_priority) curthread->td_flags |= TDF_NEEDRESCHED; if (panicstr != NULL || pri >= cpri || cold || TD_IS_INHIBITED(ctd)) return; /* * Always preempt IDLE threads. Otherwise only if the preempting * thread is an ithread. */ if (pri > preempt_thresh && cpri < PRI_MIN_IDLE) return; ctd->td_owepreempt = 1; return; } void tdq_add(struct tdq *tdq, struct thread *td, int flags) { struct td_sched *ts; int class; #ifdef SMP int cpumask; #endif TDQ_LOCK_ASSERT(tdq, MA_OWNED); 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")); ts = td->td_sched; class = PRI_BASE(td->td_pri_class); TD_SET_RUNQ(td); if (ts->ts_slice == 0) ts->ts_slice = sched_slice; /* * 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; #ifdef SMP 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; } if (td->td_priority < tdq->tdq_lowpri) tdq->tdq_lowpri = td->td_priority; #endif tdq_runq_add(tdq, ts, flags); tdq_load_add(tdq, ts); } void sched_add(struct thread *td, int flags) { struct td_sched *ts; struct tdq *tdq; #ifdef SMP int cpuid; int cpu; #endif 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); THREAD_LOCK_ASSERT(td, MA_OWNED); ts = td->td_sched; /* * Recalculate the priority before we select the target cpu or * run-queue. */ if (PRI_BASE(td->td_pri_class) == PRI_TIMESHARE) sched_priority(td); #ifdef SMP cpuid = PCPU_GET(cpuid); /* * Pick the destination cpu and if it isn't ours transfer to the * target cpu. */ if (td->td_priority <= PRI_MAX_ITHD && THREAD_CAN_MIGRATE(td)) cpu = cpuid; else if (!THREAD_CAN_MIGRATE(td)) cpu = ts->ts_cpu; else cpu = tdq_pickcpu(ts, flags); tdq = sched_setcpu(ts, cpu, flags); tdq_add(tdq, td, flags); if (cpu != cpuid) { tdq_notify(ts); return; } #else tdq = TDQ_SELF(); TDQ_LOCK(tdq); /* * Now that the thread is moving to the run-queue, set the lock * to the scheduler's lock. */ thread_lock_set(td, TDQ_LOCKPTR(tdq)); tdq_add(tdq, td, flags); #endif if (!(flags & SRQ_YIELDING)) sched_setpreempt(td); } 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); ts = td->td_sched; tdq = TDQ_CPU(ts->ts_cpu); TDQ_LOCK_ASSERT(tdq, MA_OWNED); MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); KASSERT(TD_ON_RUNQ(td), ("sched_rem: thread not on run queue")); 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; #ifdef SMP sched_smp_tick(); #endif 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 thread *td; struct tdq *tdq; td = curthread; tdq = TDQ_SELF(); mtx_assert(&Giant, MA_NOTOWNED); /* ULE relies on preemption for idle interruption. */ for (;;) { #ifdef SMP if (tdq_idled(tdq)) cpu_idle(); #else cpu_idle(); #endif } } /* * A CPU is entering for the first time or a thread is exiting. */ void sched_throw(struct thread *td) { struct tdq *tdq; tdq = TDQ_SELF(); /* * 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) { TDQ_LOCK(tdq); spinlock_exit(); } else { /* We need to switch from the run lock to the queue lock. */ thread_lock_block(td); TDQ_LOCK(tdq); thread_lock_unblock(td, TDQ_LOCKPTR(tdq)); tdq_load_rem(tdq, td->td_sched); } 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 *td) { struct td_sched *ts; struct tdq *tdq; int cpuid; /* * Finish setting up thread glue so that it begins execution in a * non-nested critical section with the scheduler lock held. */ cpuid = PCPU_GET(cpuid); tdq = TDQ_CPU(cpuid); ts = td->td_sched; if (TD_IS_IDLETHREAD(td)) td->td_lock = TDQ_LOCKPTR(tdq); MPASS(td->td_lock == TDQ_LOCKPTR(tdq)); td->td_oncpu = cpuid; TDQ_LOCKPTR(tdq)->mtx_lock = (uintptr_t)td; THREAD_LOCK_ASSERT(td, MA_OWNED | MA_NOTRECURSED); } static SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0, "Scheduler"); SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "SMP", 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, ""); SYSCTL_INT(_kern_sched, OID_AUTO, preempt_thresh, CTLFLAG_RW, &preempt_thresh, 0, ""); #ifdef SMP SYSCTL_INT(_kern_sched, OID_AUTO, pick_pri, CTLFLAG_RW, &pick_pri, 0, ""); SYSCTL_INT(_kern_sched, OID_AUTO, pick_mysql, CTLFLAG_RW, &pick_mysql, 0, ""); SYSCTL_INT(_kern_sched, OID_AUTO, affinity, CTLFLAG_RW, &affinity, 0, ""); SYSCTL_INT(_kern_sched, OID_AUTO, tryself, CTLFLAG_RW, &tryself, 0, ""); SYSCTL_INT(_kern_sched, OID_AUTO, tryselfidle, CTLFLAG_RW, &tryselfidle, 0, ""); SYSCTL_INT(_kern_sched, OID_AUTO, balance, CTLFLAG_RW, &rebalance, 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, 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"