/*- * Copyright (c) 2002-2005, 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: head/sys/kern/sched_ule.c 164939 2006-12-06 06:55:59Z julian $"); #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 /* decay 95% of `p_pctcpu' in 60 seconds; see CCPU_SHIFT before changing */ /* XXX This is bogus compatability crap for ps */ static fixpt_t ccpu = 0.95122942450071400909 * FSCALE; /* exp(-1/20) */ SYSCTL_INT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0, ""); 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 SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0, "Scheduler"); SYSCTL_STRING(_kern_sched, OID_AUTO, name, CTLFLAG_RD, "ule", 0, "Scheduler name"); static int slice_min = 1; SYSCTL_INT(_kern_sched, OID_AUTO, slice_min, CTLFLAG_RW, &slice_min, 0, ""); static int slice_max = 10; SYSCTL_INT(_kern_sched, OID_AUTO, slice_max, CTLFLAG_RW, &slice_max, 0, ""); int realstathz; int tickincr = 1 << 10; /* * The following datastructures are allocated within their parent structure * but are scheduler specific. */ /* * Thread scheduler specific section. * fields int he thread structure that are specific to this scheduler. */ 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. */ fixpt_t ts_pctcpu; /* (j) %cpu during p_swtime. */ u_char ts_rqindex; /* (j) Run queue index. */ enum { TSS_THREAD = 0x0, /* slaved to thread state */ TSS_ONRUNQ } ts_state; /* (j) thread sched specific status. */ 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 */ /* originally from kg_sched */ int skg_slptime; /* Number of ticks we vol. slept */ int skg_runtime; /* Number of ticks we were running */ }; #define ts_assign ts_procq.tqe_next /* flags kept in ts_flags */ #define TSF_ASSIGNED 0x0001 /* Thread is being migrated. */ #define TSF_BOUND 0x0002 /* Thread can not migrate. */ #define TSF_XFERABLE 0x0004 /* Thread was added as transferable. */ #define TSF_HOLD 0x0008 /* Thread is temporarily bound. */ #define TSF_REMOVED 0x0010 /* Thread was removed while ASSIGNED */ #define TSF_INTERNAL 0x0020 /* Thread added due to migration. */ #define TSF_PREEMPTED 0x0040 /* Thread was preempted */ #define TSF_DIDRUN 0x02000 /* Thread actually ran. */ #define TSF_EXIT 0x04000 /* Thread is being killed. */ static struct td_sched td_sched0; /* * The priority is primarily determined by the interactivity score. Thus, we * give lower(better) priorities to kse groups that use less CPU. The nice * value is then directly added to this to allow nice to have some effect * on latency. * * PRI_RANGE: Total priority range for timeshare threads. * PRI_NRESV: Number of nice values. * PRI_BASE: The start of the dynamic range. */ #define SCHED_PRI_RANGE (PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE + 1) #define SCHED_PRI_NRESV ((PRIO_MAX - PRIO_MIN) + 1) #define SCHED_PRI_NHALF (SCHED_PRI_NRESV / 2) #define SCHED_PRI_BASE (PRI_MIN_TIMESHARE) #define SCHED_PRI_INTERACT(score) \ ((score) * SCHED_PRI_RANGE / SCHED_INTERACT_MAX) /* * These determine the interactivity of a process. * * 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) << 10) #define SCHED_SLP_RUN_FORK ((hz / 2) << 10) #define SCHED_INTERACT_MAX (100) #define SCHED_INTERACT_HALF (SCHED_INTERACT_MAX / 2) #define SCHED_INTERACT_THRESH (30) /* * These parameters and macros determine the size of the time slice that is * granted to each thread. * * SLICE_MIN: Minimum time slice granted, in units of ticks. * SLICE_MAX: Maximum time slice granted. * SLICE_RANGE: Range of available time slices scaled by hz. * SLICE_SCALE: The number slices granted per val in the range of [0, max]. * SLICE_NICE: Determine the amount of slice granted to a scaled nice. * SLICE_NTHRESH: The nice cutoff point for slice assignment. */ #define SCHED_SLICE_MIN (slice_min) #define SCHED_SLICE_MAX (slice_max) #define SCHED_SLICE_INTERACTIVE (slice_max) #define SCHED_SLICE_NTHRESH (SCHED_PRI_NHALF - 1) #define SCHED_SLICE_RANGE (SCHED_SLICE_MAX - SCHED_SLICE_MIN + 1) #define SCHED_SLICE_SCALE(val, max) (((val) * SCHED_SLICE_RANGE) / (max)) #define SCHED_SLICE_NICE(nice) \ (SCHED_SLICE_MAX - SCHED_SLICE_SCALE((nice), SCHED_SLICE_NTHRESH)) /* * This macro determines whether or not the thread belongs on the current or * next run queue. */ #define SCHED_INTERACTIVE(td) \ (sched_interact_score(td) < SCHED_INTERACT_THRESH) #define SCHED_CURR(td, ts) \ ((ts->ts_thread->td_flags & TDF_BORROWING) || \ (ts->ts_flags & TSF_PREEMPTED) || SCHED_INTERACTIVE(td)) /* * Cpu percentage computation macros and defines. * * SCHED_CPU_TIME: Number of seconds to average the cpu usage across. * SCHED_CPU_TICKS: Number of hz ticks to average the cpu usage across. */ #define SCHED_CPU_TIME 10 #define SCHED_CPU_TICKS (hz * SCHED_CPU_TIME) /* * tdq - per processor runqs and statistics. */ struct tdq { struct runq ksq_idle; /* Queue of IDLE threads. */ struct runq ksq_timeshare[2]; /* Run queues for !IDLE. */ struct runq *ksq_next; /* Next timeshare queue. */ struct runq *ksq_curr; /* Current queue. */ int ksq_load_timeshare; /* Load for timeshare. */ int ksq_load; /* Aggregate load. */ short ksq_nice[SCHED_PRI_NRESV]; /* threadss in each nice bin. */ short ksq_nicemin; /* Least nice. */ #ifdef SMP int ksq_transferable; LIST_ENTRY(tdq) ksq_siblings; /* Next in tdq group. */ struct tdq_group *ksq_group; /* Our processor group. */ volatile struct td_sched *ksq_assigned; /* assigned by another CPU. */ #else int ksq_sysload; /* For loadavg, !ITHD load. */ #endif }; #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 ksg_cpus; /* Count of CPUs in this tdq group. */ cpumask_t ksg_cpumask; /* Mask of cpus in this group. */ cpumask_t ksg_idlemask; /* Idle cpus in this group. */ cpumask_t ksg_mask; /* Bit mask for first cpu. */ int ksg_load; /* Total load of this group. */ int ksg_transferable; /* Transferable load of this group. */ LIST_HEAD(, tdq) ksg_members; /* Linked list of all members. */ }; #endif /* * One kse queue per processor. */ #ifdef SMP static cpumask_t tdq_idle; static int ksg_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_SELF() (&tdq_cpu) #define TDQ_CPU(x) (&tdq_cpu) #endif static struct td_sched *sched_choose(void); /* XXX Should be thread * */ static void sched_slice(struct td_sched *); 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 *); static void tdq_nice_add(struct tdq *, int); static void tdq_nice_rem(struct tdq *, int); void tdq_print(int cpu); #ifdef SMP static int tdq_transfer(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 tdq_move(struct tdq *, int); static int tdq_idled(struct tdq *); static void tdq_notify(struct td_sched *, int); static void tdq_assign(struct tdq *); static struct td_sched *tdq_steal(struct tdq *, int); #define THREAD_CAN_MIGRATE(ts) \ ((ts)->ts_thread->td_pinned == 0 && ((ts)->ts_flags & TSF_BOUND) == 0) #endif void tdq_print(int cpu) { struct tdq *tdq; int i; tdq = TDQ_CPU(cpu); printf("tdq:\n"); printf("\tload: %d\n", tdq->ksq_load); printf("\tload TIMESHARE: %d\n", tdq->ksq_load_timeshare); #ifdef SMP printf("\tload transferable: %d\n", tdq->ksq_transferable); #endif printf("\tnicemin:\t%d\n", tdq->ksq_nicemin); printf("\tnice counts:\n"); for (i = 0; i < SCHED_PRI_NRESV; i++) if (tdq->ksq_nice[i]) printf("\t\t%d = %d\n", i - SCHED_PRI_NHALF, tdq->ksq_nice[i]); } static __inline void tdq_runq_add(struct tdq *tdq, struct td_sched *ts, int flags) { #ifdef SMP if (THREAD_CAN_MIGRATE(ts)) { tdq->ksq_transferable++; tdq->ksq_group->ksg_transferable++; ts->ts_flags |= TSF_XFERABLE; } #endif if (ts->ts_flags & TSF_PREEMPTED) flags |= SRQ_PREEMPTED; 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->ksq_transferable--; tdq->ksq_group->ksg_transferable--; ts->ts_flags &= ~TSF_XFERABLE; } #endif 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); if (class == PRI_TIMESHARE) tdq->ksq_load_timeshare++; tdq->ksq_load++; CTR1(KTR_SCHED, "load: %d", tdq->ksq_load); if (class != PRI_ITHD && (ts->ts_thread->td_proc->p_flag & P_NOLOAD) == 0) #ifdef SMP tdq->ksq_group->ksg_load++; #else tdq->ksq_sysload++; #endif if (ts->ts_thread->td_pri_class == PRI_TIMESHARE) tdq_nice_add(tdq, ts->ts_thread->td_proc->p_nice); } 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_TIMESHARE) tdq->ksq_load_timeshare--; if (class != PRI_ITHD && (ts->ts_thread->td_proc->p_flag & P_NOLOAD) == 0) #ifdef SMP tdq->ksq_group->ksg_load--; #else tdq->ksq_sysload--; #endif tdq->ksq_load--; CTR1(KTR_SCHED, "load: %d", tdq->ksq_load); ts->ts_runq = NULL; if (ts->ts_thread->td_pri_class == PRI_TIMESHARE) tdq_nice_rem(tdq, ts->ts_thread->td_proc->p_nice); } static void tdq_nice_add(struct tdq *tdq, int nice) { mtx_assert(&sched_lock, MA_OWNED); /* Normalize to zero. */ tdq->ksq_nice[nice + SCHED_PRI_NHALF]++; if (nice < tdq->ksq_nicemin || tdq->ksq_load_timeshare == 1) tdq->ksq_nicemin = nice; } static void tdq_nice_rem(struct tdq *tdq, int nice) { int n; mtx_assert(&sched_lock, MA_OWNED); /* Normalize to zero. */ n = nice + SCHED_PRI_NHALF; tdq->ksq_nice[n]--; KASSERT(tdq->ksq_nice[n] >= 0, ("Negative nice count.")); /* * If this wasn't the smallest nice value or there are more in * this bucket we can just return. Otherwise we have to recalculate * the smallest nice. */ if (nice != tdq->ksq_nicemin || tdq->ksq_nice[n] != 0 || tdq->ksq_load_timeshare == 0) return; for (; n < SCHED_PRI_NRESV; n++) if (tdq->ksq_nice[n]) { tdq->ksq_nicemin = n - SCHED_PRI_NHALF; return; } } #ifdef SMP /* * 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 *ksg; int cnt; int i; bal_tick = ticks + (random() % (hz * 2)); if (smp_started == 0) return; low = high = NULL; i = random() % (ksg_maxid + 1); for (cnt = 0; cnt <= ksg_maxid; cnt++) { ksg = TDQ_GROUP(i); /* * Find the CPU with the highest load that has some * threads to transfer. */ if ((high == NULL || ksg->ksg_load > high->ksg_load) && ksg->ksg_transferable) high = ksg; if (low == NULL || ksg->ksg_load < low->ksg_load) low = ksg; if (++i > ksg_maxid) i = 0; } if (low != NULL && high != NULL && high != low) sched_balance_pair(LIST_FIRST(&high->ksg_members), LIST_FIRST(&low->ksg_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 <= ksg_maxid; i++) sched_balance_group(TDQ_GROUP(i)); } static void sched_balance_group(struct tdq_group *ksg) { struct tdq *tdq; struct tdq *high; struct tdq *low; int load; if (ksg->ksg_transferable == 0) return; low = NULL; high = NULL; LIST_FOREACH(tdq, &ksg->ksg_members, ksq_siblings) { load = tdq->ksq_load; if (high == NULL || load > high->ksq_load) high = tdq; if (low == NULL || load < low->ksq_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->ksq_group == low->ksq_group) { transferable = high->ksq_transferable; high_load = high->ksq_load; low_load = low->ksq_load; } else { transferable = high->ksq_group->ksg_transferable; high_load = high->ksq_group->ksg_load; low_load = low->ksq_group->ksg_load; } if (transferable == 0) return; /* * Determine what the imbalance is and then adjust that to how many * kses 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 *ksg; ksg = tdq->ksq_group; LIST_FOREACH(tdq, &ksg->ksg_members, ksq_siblings) { if (tdq == from || tdq->ksq_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", ksg->ksg_transferable); } if (tdq == to) return; ts->ts_state = TSS_THREAD; tdq_runq_rem(tdq, ts); tdq_load_rem(tdq, ts); tdq_notify(ts, cpu); } static int tdq_idled(struct tdq *tdq) { struct tdq_group *ksg; struct tdq *steal; struct td_sched *ts; ksg = tdq->ksq_group; /* * If we're in a cpu group, try and steal kses from another cpu in * the group before idling. */ if (ksg->ksg_cpus > 1 && ksg->ksg_transferable) { LIST_FOREACH(steal, &ksg->ksg_members, ksq_siblings) { if (steal == tdq || steal->ksq_transferable == 0) continue; ts = tdq_steal(steal, 0); if (ts == NULL) continue; ts->ts_state = TSS_THREAD; tdq_runq_rem(steal, ts); tdq_load_rem(steal, ts); ts->ts_cpu = PCPU_GET(cpuid); ts->ts_flags |= TSF_INTERNAL | TSF_HOLD; sched_add(ts->ts_thread, SRQ_YIELDING); return (0); } } /* * 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. */ ksg->ksg_idlemask |= PCPU_GET(cpumask); if (ksg->ksg_idlemask != ksg->ksg_cpumask) return (1); atomic_set_int(&tdq_idle, ksg->ksg_mask); return (1); } static void tdq_assign(struct tdq *tdq) { struct td_sched *nts; struct td_sched *ts; do { *(volatile struct td_sched **)&ts = tdq->ksq_assigned; } while(!atomic_cmpset_ptr((volatile uintptr_t *)&tdq->ksq_assigned, (uintptr_t)ts, (uintptr_t)NULL)); for (; ts != NULL; ts = nts) { nts = ts->ts_assign; tdq->ksq_group->ksg_load--; tdq->ksq_load--; ts->ts_flags &= ~TSF_ASSIGNED; if (ts->ts_flags & TSF_REMOVED) { ts->ts_flags &= ~TSF_REMOVED; continue; } ts->ts_flags |= TSF_INTERNAL | TSF_HOLD; sched_add(ts->ts_thread, SRQ_YIELDING); } } static void tdq_notify(struct td_sched *ts, int cpu) { struct tdq *tdq; struct thread *td; struct pcpu *pcpu; int class; int prio; tdq = TDQ_CPU(cpu); /* XXX */ class = PRI_BASE(ts->ts_thread->td_pri_class); if ((class == PRI_TIMESHARE || class == PRI_REALTIME) && (tdq_idle & tdq->ksq_group->ksg_mask)) atomic_clear_int(&tdq_idle, tdq->ksq_group->ksg_mask); tdq->ksq_group->ksg_load++; tdq->ksq_load++; ts->ts_cpu = cpu; ts->ts_flags |= TSF_ASSIGNED; prio = ts->ts_thread->td_priority; /* * Place a thread on another cpu's queue and force a resched. */ do { *(volatile struct td_sched **)&ts->ts_assign = tdq->ksq_assigned; } while(!atomic_cmpset_ptr((volatile uintptr_t *)&tdq->ksq_assigned, (uintptr_t)ts->ts_assign, (uintptr_t)ts)); /* * Without sched_lock we could lose a race where we set NEEDRESCHED * on a thread that is switched out before the IPI is delivered. This * would lead us to miss the resched. This will be a problem once * sched_lock is pushed down. */ pcpu = pcpu_find(cpu); td = pcpu->pc_curthread; if (ts->ts_thread->td_priority < td->td_priority || td == pcpu->pc_idlethread) { td->td_flags |= TDF_NEEDRESCHED; ipi_selected(1 << cpu, IPI_AST); } } 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)) 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. */ if ((ts = runq_steal(tdq->ksq_next)) != NULL) return (ts); if ((ts = runq_steal(tdq->ksq_curr)) != NULL) return (ts); if (stealidle) return (runq_steal(&tdq->ksq_idle)); return (NULL); } int tdq_transfer(struct tdq *tdq, struct td_sched *ts, int class) { struct tdq_group *nksg; struct tdq_group *ksg; struct tdq *old; int cpu; int idx; if (smp_started == 0) return (0); cpu = 0; /* * If our load exceeds a certain threshold we should attempt to * reassign this thread. The first candidate is the cpu that * originally ran the thread. If it is idle, assign it there, * otherwise, pick an idle cpu. * * The threshold at which we start to reassign kses has a large impact * on the overall performance of the system. Tuned too high and * some CPUs may idle. Too low and there will be excess migration * and context switches. */ old = TDQ_CPU(ts->ts_cpu); nksg = old->ksq_group; ksg = tdq->ksq_group; if (tdq_idle) { if (tdq_idle & nksg->ksg_mask) { cpu = ffs(nksg->ksg_idlemask); if (cpu) { CTR2(KTR_SCHED, "tdq_transfer: %p found old cpu %X " "in idlemask.", ts, cpu); goto migrate; } } /* * Multiple cpus could find this bit simultaneously * but the race shouldn't be terrible. */ cpu = ffs(tdq_idle); if (cpu) { CTR2(KTR_SCHED, "tdq_transfer: %p found %X " "in idlemask.", ts, cpu); goto migrate; } } idx = 0; #if 0 if (old->ksq_load < tdq->ksq_load) { cpu = ts->ts_cpu + 1; CTR2(KTR_SCHED, "tdq_transfer: %p old cpu %X " "load less than ours.", ts, cpu); goto migrate; } /* * No new CPU was found, look for one with less load. */ for (idx = 0; idx <= ksg_maxid; idx++) { nksg = TDQ_GROUP(idx); if (nksg->ksg_load /*+ (nksg->ksg_cpus * 2)*/ < ksg->ksg_load) { cpu = ffs(nksg->ksg_cpumask); CTR2(KTR_SCHED, "tdq_transfer: %p cpu %X load less " "than ours.", ts, cpu); goto migrate; } } #endif /* * If another cpu in this group has idled, assign a thread over * to them after checking to see if there are idled groups. */ if (ksg->ksg_idlemask) { cpu = ffs(ksg->ksg_idlemask); if (cpu) { CTR2(KTR_SCHED, "tdq_transfer: %p cpu %X idle in " "group.", ts, cpu); goto migrate; } } return (0); migrate: /* * Now that we've found an idle CPU, migrate the thread. */ cpu--; ts->ts_runq = NULL; tdq_notify(ts, cpu); return (1); } #endif /* SMP */ /* * Pick the highest priority task we have and return it. */ static struct td_sched * tdq_choose(struct tdq *tdq) { struct runq *swap; struct td_sched *ts; int nice; mtx_assert(&sched_lock, MA_OWNED); swap = NULL; for (;;) { ts = runq_choose(tdq->ksq_curr); if (ts == NULL) { /* * We already swapped once and didn't get anywhere. */ if (swap) break; swap = tdq->ksq_curr; tdq->ksq_curr = tdq->ksq_next; tdq->ksq_next = swap; continue; } /* * If we encounter a slice of 0 the td_sched is in a * TIMESHARE td_sched group and its nice was too far out * of the range that receives slices. */ nice = ts->ts_thread->td_proc->p_nice + (0 - tdq->ksq_nicemin); #if 0 if (ts->ts_slice == 0 || (nice > SCHED_SLICE_NTHRESH && ts->ts_thread->td_proc->p_nice != 0)) { runq_remove(ts->ts_runq, ts); sched_slice(ts); ts->ts_runq = tdq->ksq_next; runq_add(ts->ts_runq, ts, 0); continue; } #endif return (ts); } return (runq_choose(&tdq->ksq_idle)); } static void tdq_setup(struct tdq *tdq) { runq_init(&tdq->ksq_timeshare[0]); runq_init(&tdq->ksq_timeshare[1]); runq_init(&tdq->ksq_idle); tdq->ksq_curr = &tdq->ksq_timeshare[0]; tdq->ksq_next = &tdq->ksq_timeshare[1]; tdq->ksq_load = 0; tdq->ksq_load_timeshare = 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; slice_min = (hz/100); /* 10ms */ slice_max = (hz/7); /* ~140ms */ #ifdef SMP balance_groups = 0; /* * Initialize the tdqs. */ for (i = 0; i < MAXCPU; i++) { struct tdq *ksq; ksq = &tdq_cpu[i]; ksq->ksq_assigned = NULL; tdq_setup(&tdq_cpu[i]); } if (smp_topology == NULL) { struct tdq_group *ksg; struct tdq *ksq; int cpus; for (cpus = 0, i = 0; i < MAXCPU; i++) { if (CPU_ABSENT(i)) continue; ksq = &tdq_cpu[i]; ksg = &tdq_groups[cpus]; /* * Setup a tdq group with one member. */ ksq->ksq_transferable = 0; ksq->ksq_group = ksg; ksg->ksg_cpus = 1; ksg->ksg_idlemask = 0; ksg->ksg_cpumask = ksg->ksg_mask = 1 << i; ksg->ksg_load = 0; ksg->ksg_transferable = 0; LIST_INIT(&ksg->ksg_members); LIST_INSERT_HEAD(&ksg->ksg_members, ksq, ksq_siblings); cpus++; } ksg_maxid = cpus - 1; } else { struct tdq_group *ksg; struct cpu_group *cg; int j; for (i = 0; i < smp_topology->ct_count; i++) { cg = &smp_topology->ct_group[i]; ksg = &tdq_groups[i]; /* * Initialize the group. */ ksg->ksg_idlemask = 0; ksg->ksg_load = 0; ksg->ksg_transferable = 0; ksg->ksg_cpus = cg->cg_count; ksg->ksg_cpumask = cg->cg_mask; LIST_INIT(&ksg->ksg_members); /* * Find all of the group members and add them. */ for (j = 0; j < MAXCPU; j++) { if ((cg->cg_mask & (1 << j)) != 0) { if (ksg->ksg_mask == 0) ksg->ksg_mask = 1 << j; tdq_cpu[j].ksq_transferable = 0; tdq_cpu[j].ksq_group = ksg; LIST_INSERT_HEAD(&ksg->ksg_members, &tdq_cpu[j], ksq_siblings); } } if (ksg->ksg_cpus > 1) balance_groups = 1; } ksg_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; slice_min = (realstathz/100); /* 10ms */ slice_max = (realstathz/7); /* ~140ms */ tickincr = (hz << 10) / realstathz; /* * XXX This does not work for values of stathz that are much * larger than hz. */ if (tickincr == 0) tickincr = 1; mtx_unlock_spin(&sched_lock); } /* * Scale the scheduling priority according to the "interactivity" of this * process. */ static void sched_priority(struct thread *td) { int pri; if (td->td_pri_class != PRI_TIMESHARE) return; pri = SCHED_PRI_INTERACT(sched_interact_score(td)); pri += SCHED_PRI_BASE; pri += td->td_proc->p_nice; if (pri > PRI_MAX_TIMESHARE) pri = PRI_MAX_TIMESHARE; else if (pri < PRI_MIN_TIMESHARE) pri = PRI_MIN_TIMESHARE; sched_user_prio(td, pri); return; } /* * Calculate a time slice based on the properties of the process * and the runq that we're on. This is only for PRI_TIMESHARE threads. */ static void sched_slice(struct td_sched *ts) { struct tdq *tdq; struct thread *td; td = ts->ts_thread; tdq = TDQ_CPU(ts->ts_cpu); if (td->td_flags & TDF_BORROWING) { ts->ts_slice = SCHED_SLICE_MIN; return; } /* * Rationale: * Threads in interactive procs get a minimal slice so that we * quickly notice if it abuses its advantage. * * Threads in non-interactive procs are assigned a slice that is * based on the procs nice value relative to the least nice procs * on the run queue for this cpu. * * If the thread is less nice than all others it gets the maximum * slice and other threads will adjust their slice relative to * this when they first expire. * * There is 20 point window that starts relative to the least * nice td_sched on the run queue. Slice size is determined by * the td_sched distance from the last nice thread. * * If the td_sched is outside of the window it will get no slice * and will be reevaluated each time it is selected on the * run queue. The exception to this is nice 0 procs when * a nice -20 is running. They are always granted a minimum * slice. */ if (!SCHED_INTERACTIVE(td)) { int nice; nice = td->td_proc->p_nice + (0 - tdq->ksq_nicemin); if (tdq->ksq_load_timeshare == 0 || td->td_proc->p_nice < tdq->ksq_nicemin) ts->ts_slice = SCHED_SLICE_MAX; else if (nice <= SCHED_SLICE_NTHRESH) ts->ts_slice = SCHED_SLICE_NICE(nice); else if (td->td_proc->p_nice == 0) ts->ts_slice = SCHED_SLICE_MIN; else ts->ts_slice = SCHED_SLICE_MIN; /* 0 */ } else ts->ts_slice = SCHED_SLICE_INTERACTIVE; 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. * This routine will not operate correctly when slp or run times have been * adjusted to more than double their maximum. */ static void sched_interact_update(struct thread *td) { int sum; sum = td->td_sched->skg_runtime + td->td_sched->skg_slptime; if (sum < SCHED_SLP_RUN_MAX) 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) { td->td_sched->skg_runtime /= 2; td->td_sched->skg_slptime /= 2; return; } td->td_sched->skg_runtime = (td->td_sched->skg_runtime / 5) * 4; td->td_sched->skg_slptime = (td->td_sched->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); } /* * This can happen if slptime and runtime are 0. */ return (0); } /* * Very early in the boot some setup of scheduler-specific * parts of proc0 and of soem scheduler resources needs to be done. * Called from: * proc0_init() */ void schedinit(void) { /* * Set up the scheduler specific parts of proc0. */ proc0.p_sched = NULL; /* XXX */ thread0.td_sched = &td_sched0; td_sched0.ts_thread = &thread0; td_sched0.ts_state = TSS_THREAD; } /* * 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_MAX. */ int sched_rr_interval(void) { return (SCHED_SLICE_MAX); } static void sched_pctcpu_update(struct td_sched *ts) { /* * Adjust counters and watermark for pctcpu calc. */ if (ts->ts_ltick > ticks - SCHED_CPU_TICKS) { /* * Shift the tick count out so that the divide doesn't * round away our results. */ ts->ts_ticks <<= 10; ts->ts_ticks = (ts->ts_ticks / (ticks - ts->ts_ftick)) * SCHED_CPU_TICKS; ts->ts_ticks >>= 10; } else ts->ts_ticks = 0; ts->ts_ltick = ticks; ts->ts_ftick = ts->ts_ltick - SCHED_CPU_TICKS; } 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; mtx_assert(&sched_lock, MA_OWNED); if (td->td_priority == prio) return; if (TD_ON_RUNQ(td)) { /* * If the priority has been elevated due to priority * propagation, we may have to move ourselves to a new * queue. We still call adjustrunqueue below in case kse * needs to fix things up. */ if (prio < td->td_priority && ts->ts_runq != NULL && (ts->ts_flags & TSF_ASSIGNED) == 0 && ts->ts_runq != TDQ_CPU(ts->ts_cpu)->ksq_curr) { runq_remove(ts->ts_runq, ts); ts->ts_runq = TDQ_CPU(ts->ts_cpu)->ksq_curr; runq_add(ts->ts_runq, ts, 0); } /* * Hold this td_sched on this cpu so that sched_prio() doesn't * cause excessive migration. We only want migration to * happen as the result of a wakeup. */ ts->ts_flags |= TSF_HOLD; adjustrunqueue(td, prio); ts->ts_flags &= ~TSF_HOLD; } 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 *ksq; struct td_sched *ts; mtx_assert(&sched_lock, MA_OWNED); ts = td->td_sched; ksq = TDQ_SELF(); 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(). */ if (td == PCPU_GET(idlethread)) { TD_SET_CAN_RUN(td); } else if ((ts->ts_flags & TSF_ASSIGNED) == 0) { /* We are ending our run so make our slot available again */ tdq_load_rem(ksq, ts); if (TD_IS_RUNNING(td)) { /* * Don't allow the thread to migrate * from a preemption. */ ts->ts_flags |= TSF_HOLD; setrunqueue(td, (flags & SW_PREEMPT) ? SRQ_OURSELF|SRQ_YIELDING|SRQ_PREEMPTED : SRQ_OURSELF|SRQ_YIELDING); ts->ts_flags &= ~TSF_HOLD; } } 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. */ newtd->td_sched->ts_flags |= TSF_DIDRUN; newtd->td_sched->ts_runq = ksq->ksq_curr; 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); #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); } void sched_nice(struct proc *p, int nice) { struct td_sched *ts; struct thread *td; struct tdq *tdq; PROC_LOCK_ASSERT(p, MA_OWNED); mtx_assert(&sched_lock, MA_OWNED); /* * We need to adjust the nice counts for running threads. */ FOREACH_THREAD_IN_PROC(p, td) { if (td->td_pri_class == PRI_TIMESHARE) { ts = td->td_sched; if (ts->ts_runq == NULL) continue; tdq = TDQ_CPU(ts->ts_cpu); tdq_nice_rem(tdq, p->p_nice); tdq_nice_add(tdq, nice); } } p->p_nice = nice; FOREACH_THREAD_IN_PROC(p, td) { sched_priority(td); td->td_flags |= TDF_NEEDRESCHED; } } void sched_sleep(struct thread *td) { mtx_assert(&sched_lock, MA_OWNED); td->td_sched->ts_slptime = ticks; } void sched_wakeup(struct thread *td) { mtx_assert(&sched_lock, MA_OWNED); /* * Let the procs know how long we slept for. This is because process * interactivity behavior is modeled in the procs. */ if (td->td_sched->ts_slptime) { int hzticks; hzticks = (ticks - td->td_sched->ts_slptime) << 10; if (hzticks >= SCHED_SLP_RUN_MAX) { td->td_sched->skg_slptime = SCHED_SLP_RUN_MAX; td->td_sched->skg_runtime = 1; } else { td->td_sched->skg_slptime += hzticks; sched_interact_update(td); } sched_priority(td); sched_slice(td->td_sched); td->td_sched->ts_slptime = 0; } setrunqueue(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) { mtx_assert(&sched_lock, MA_OWNED); sched_fork_thread(td, child); } void sched_fork_thread(struct thread *td, struct thread *child) { struct td_sched *ts; struct td_sched *ts2; child->td_sched->skg_slptime = td->td_sched->skg_slptime; child->td_sched->skg_runtime = td->td_sched->skg_runtime; child->td_user_pri = td->td_user_pri; child->td_base_user_pri = td->td_base_user_pri; sched_interact_fork(child); td->td_sched->skg_runtime += tickincr; sched_interact_update(td); sched_newthread(child); ts = td->td_sched; ts2 = child->td_sched; ts2->ts_slice = 1; /* Attempt to quickly learn interactivity. */ ts2->ts_cpu = ts->ts_cpu; ts2->ts_runq = NULL; /* Grab our parents cpu estimation information. */ ts2->ts_ticks = ts->ts_ticks; ts2->ts_ltick = ts->ts_ltick; ts2->ts_ftick = ts->ts_ftick; } void sched_class(struct thread *td, int class) { struct tdq *tdq; struct td_sched *ts; int nclass; int oclass; mtx_assert(&sched_lock, MA_OWNED); if (td->td_pri_class == class) return; nclass = PRI_BASE(class); oclass = PRI_BASE(td->td_pri_class); ts = td->td_sched; if (!((ts->ts_state != TSS_ONRUNQ && ts->ts_state != TSS_THREAD) || ts->ts_runq == NULL)) { tdq = TDQ_CPU(ts->ts_cpu); #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 (ts->ts_state == TSS_ONRUNQ) { if (THREAD_CAN_MIGRATE(ts)) { tdq->ksq_transferable--; tdq->ksq_group->ksg_transferable--; } if (THREAD_CAN_MIGRATE(ts)) { tdq->ksq_transferable++; tdq->ksq_group->ksg_transferable++; } } #endif if (oclass == PRI_TIMESHARE) { tdq->ksq_load_timeshare--; tdq_nice_rem(tdq, td->td_proc->p_nice); } if (nclass == PRI_TIMESHARE) { tdq->ksq_load_timeshare++; tdq_nice_add(tdq, td->td_proc->p_nice); } } 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) { CTR3(KTR_SCHED, "sched_exit: %p(%s) prio %d", child, child->td_proc->p_comm, child->td_priority); sched_exit_thread(FIRST_THREAD_IN_PROC(p), child); } void sched_exit_thread(struct thread *td, struct thread *child) { CTR3(KTR_SCHED, "sched_exit_thread: %p(%s) prio %d", child, childproc->p_comm, child->td_priority); td->td_sched->skg_runtime += child->td_sched->skg_runtime; sched_interact_update(td); tdq_load_rem(TDQ_CPU(child->td_sched->ts_cpu), child->td_sched); } 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) { mtx_lock_spin(&sched_lock); td->td_priority = td->td_user_pri; td->td_base_pri = td->td_user_pri; mtx_unlock_spin(&sched_lock); } } void sched_clock(struct thread *td) { struct tdq *tdq; struct td_sched *ts; mtx_assert(&sched_lock, MA_OWNED); tdq = TDQ_SELF(); #ifdef SMP if (ticks >= bal_tick) sched_balance(); if (ticks >= gbal_tick && balance_groups) sched_balance_groups(); /* * We could have been assigned a non real-time thread without an * IPI. */ if (tdq->ksq_assigned) tdq_assign(tdq); /* Potentially sets NEEDRESCHED */ #endif ts = td->td_sched; /* Adjust ticks for pctcpu */ ts->ts_ticks++; ts->ts_ltick = ticks; /* Go up to one second beyond our max and then trim back down */ if (ts->ts_ftick + SCHED_CPU_TICKS + hz < ts->ts_ltick) sched_pctcpu_update(ts); if (td->td_flags & TDF_IDLETD) return; /* * 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. */ tdq_load_rem(tdq, ts); sched_priority(td); sched_slice(ts); if (SCHED_CURR(td, ts)) ts->ts_runq = tdq->ksq_curr; else ts->ts_runq = tdq->ksq_next; tdq_load_add(tdq, ts); td->td_flags |= TDF_NEEDRESCHED; } int sched_runnable(void) { struct tdq *tdq; int load; load = 1; tdq = TDQ_SELF(); #ifdef SMP if (tdq->ksq_assigned) { mtx_lock_spin(&sched_lock); tdq_assign(tdq); mtx_unlock_spin(&sched_lock); } #endif if ((curthread->td_flags & TDF_IDLETD) != 0) { if (tdq->ksq_load > 0) goto out; } else if (tdq->ksq_load - 1 > 0) goto out; load = 0; out: return (load); } struct td_sched * sched_choose(void) { struct tdq *tdq; struct td_sched *ts; mtx_assert(&sched_lock, MA_OWNED); tdq = TDQ_SELF(); #ifdef SMP restart: if (tdq->ksq_assigned) tdq_assign(tdq); #endif ts = tdq_choose(tdq); if (ts) { #ifdef SMP if (ts->ts_thread->td_pri_class == PRI_IDLE) if (tdq_idled(tdq) == 0) goto restart; #endif tdq_runq_rem(tdq, ts); ts->ts_state = TSS_THREAD; ts->ts_flags &= ~TSF_PREEMPTED; return (ts); } #ifdef SMP if (tdq_idled(tdq) == 0) goto restart; #endif return (NULL); } void sched_add(struct thread *td, int flags) { struct tdq *tdq; struct td_sched *ts; int preemptive; int canmigrate; int class; 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); mtx_assert(&sched_lock, MA_OWNED); ts = td->td_sched; canmigrate = 1; preemptive = !(flags & SRQ_YIELDING); class = PRI_BASE(td->td_pri_class); tdq = TDQ_SELF(); ts->ts_flags &= ~TSF_INTERNAL; #ifdef SMP if (ts->ts_flags & TSF_ASSIGNED) { if (ts->ts_flags & TSF_REMOVED) ts->ts_flags &= ~TSF_REMOVED; return; } canmigrate = THREAD_CAN_MIGRATE(ts); /* * Don't migrate running threads here. Force the long term balancer * to do it. */ if (ts->ts_flags & TSF_HOLD) { ts->ts_flags &= ~TSF_HOLD; canmigrate = 0; } #endif KASSERT(ts->ts_state != TSS_ONRUNQ, ("sched_add: thread %p (%s) already in run queue", td, td->td_proc->p_comm)); KASSERT(td->td_proc->p_sflag & PS_INMEM, ("sched_add: process swapped out")); KASSERT(ts->ts_runq == NULL, ("sched_add: thread %p is still assigned to a run queue", td)); if (flags & SRQ_PREEMPTED) ts->ts_flags |= TSF_PREEMPTED; switch (class) { case PRI_ITHD: case PRI_REALTIME: ts->ts_runq = tdq->ksq_curr; ts->ts_slice = SCHED_SLICE_MAX; if (canmigrate) ts->ts_cpu = PCPU_GET(cpuid); break; case PRI_TIMESHARE: if (SCHED_CURR(td, ts)) ts->ts_runq = tdq->ksq_curr; else ts->ts_runq = tdq->ksq_next; break; case PRI_IDLE: /* * This is for priority prop. */ if (ts->ts_thread->td_priority < PRI_MIN_IDLE) ts->ts_runq = tdq->ksq_curr; else ts->ts_runq = &tdq->ksq_idle; ts->ts_slice = SCHED_SLICE_MIN; break; default: panic("Unknown pri class."); break; } #ifdef SMP /* * If this thread is pinned or bound, notify the target cpu. */ if (!canmigrate && ts->ts_cpu != PCPU_GET(cpuid) ) { ts->ts_runq = NULL; tdq_notify(ts, ts->ts_cpu); return; } /* * If we had been idle, clear our bit in the group and potentially * the global bitmap. If not, see if we should transfer this thread. */ if ((class == PRI_TIMESHARE || class == PRI_REALTIME) && (tdq->ksq_group->ksg_idlemask & PCPU_GET(cpumask)) != 0) { /* * Check to see if our group is unidling, and if so, remove it * from the global idle mask. */ if (tdq->ksq_group->ksg_idlemask == tdq->ksq_group->ksg_cpumask) atomic_clear_int(&tdq_idle, tdq->ksq_group->ksg_mask); /* * Now remove ourselves from the group specific idle mask. */ tdq->ksq_group->ksg_idlemask &= ~PCPU_GET(cpumask); } else if (canmigrate && tdq->ksq_load > 1 && class != PRI_ITHD) if (tdq_transfer(tdq, ts, class)) return; ts->ts_cpu = PCPU_GET(cpuid); #endif if (td->td_priority < curthread->td_priority && ts->ts_runq == tdq->ksq_curr) curthread->td_flags |= TDF_NEEDRESCHED; if (preemptive && maybe_preempt(td)) return; ts->ts_state = TSS_ONRUNQ; tdq_runq_add(tdq, ts, flags); tdq_load_add(tdq, ts); } 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); mtx_assert(&sched_lock, MA_OWNED); ts = td->td_sched; ts->ts_flags &= ~TSF_PREEMPTED; if (ts->ts_flags & TSF_ASSIGNED) { ts->ts_flags |= TSF_REMOVED; return; } KASSERT((ts->ts_state == TSS_ONRUNQ), ("sched_rem: thread not on run queue")); ts->ts_state = TSS_THREAD; tdq = TDQ_CPU(ts->ts_cpu); tdq_runq_rem(tdq, ts); tdq_load_rem(tdq, ts); } 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); mtx_lock_spin(&sched_lock); if (ts->ts_ticks) { int rtick; /* * Don't update more frequently than twice a second. Allowing * this causes the cpu usage to decay away too quickly due to * rounding errors. */ if (ts->ts_ftick + SCHED_CPU_TICKS < ts->ts_ltick || ts->ts_ltick < (ticks - (hz / 2))) sched_pctcpu_update(ts); /* How many rtick per second ? */ rtick = min(ts->ts_ticks / SCHED_CPU_TIME, SCHED_CPU_TICKS); pctcpu = (FSCALE * ((FSCALE * rtick)/realstathz)) >> FSHIFT; } td->td_proc->p_swtime = ts->ts_ltick - ts->ts_ftick; mtx_unlock_spin(&sched_lock); return (pctcpu); } void sched_bind(struct thread *td, int cpu) { struct td_sched *ts; mtx_assert(&sched_lock, MA_OWNED); ts = td->td_sched; ts->ts_flags |= TSF_BOUND; #ifdef SMP if (PCPU_GET(cpuid) == cpu) return; /* sched_rem without the runq_remove */ ts->ts_state = TSS_THREAD; tdq_load_rem(TDQ_CPU(ts->ts_cpu), ts); tdq_notify(ts, 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) { mtx_assert(&sched_lock, MA_OWNED); td->td_sched->ts_flags &= ~TSF_BOUND; } int sched_is_bound(struct thread *td) { mtx_assert(&sched_lock, MA_OWNED); return (td->td_sched->ts_flags & TSF_BOUND); } void sched_relinquish(struct thread *td) { mtx_lock_spin(&sched_lock); if (td->td_pri_class == PRI_TIMESHARE) sched_prio(td, PRI_MAX_TIMESHARE); mi_switch(SW_VOL, NULL); mtx_unlock_spin(&sched_lock); } int sched_load(void) { #ifdef SMP int total; int i; total = 0; for (i = 0; i <= ksg_maxid; i++) total += TDQ_GROUP(i)->ksg_load; return (total); #else return (TDQ_SELF()->ksq_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) { } #define KERN_SWITCH_INCLUDE 1 #include "kern/kern_switch.c"