/*- * Copyright (c) 2002-2003, Jeffrey Roberson <jeff@freebsd.org> * 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 <sys/cdefs.h> __FBSDID("$FreeBSD$"); #include <sys/param.h> #include <sys/systm.h> #include <sys/kernel.h> #include <sys/ktr.h> #include <sys/lock.h> #include <sys/mutex.h> #include <sys/proc.h> #include <sys/resource.h> #include <sys/resourcevar.h> #include <sys/sched.h> #include <sys/smp.h> #include <sys/sx.h> #include <sys/sysctl.h> #include <sys/sysproto.h> #include <sys/vmmeter.h> #ifdef DDB #include <ddb/ddb.h> #endif #ifdef KTRACE #include <sys/uio.h> #include <sys/ktrace.h> #endif #include <machine/cpu.h> #include <machine/smp.h> #define KTR_ULE KTR_NFS /* 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 SYSCTL_NODE(_kern, OID_AUTO, sched, CTLFLAG_RW, 0, "SCHED"); static int sched_strict; SYSCTL_INT(_kern_sched, OID_AUTO, strict, CTLFLAG_RD, &sched_strict, 0, ""); 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; #ifdef SMP /* Callout to handle load balancing SMP systems. */ static struct callout kseq_lb_callout; #endif /* * These datastructures are allocated within their parent datastructure but * are scheduler specific. */ struct ke_sched { int ske_slice; struct runq *ske_runq; /* The following variables are only used for pctcpu calculation */ int ske_ltick; /* Last tick that we were running on */ int ske_ftick; /* First tick that we were running on */ int ske_ticks; /* Tick count */ /* CPU that we have affinity for. */ u_char ske_cpu; }; #define ke_slice ke_sched->ske_slice #define ke_runq ke_sched->ske_runq #define ke_ltick ke_sched->ske_ltick #define ke_ftick ke_sched->ske_ftick #define ke_ticks ke_sched->ske_ticks #define ke_cpu ke_sched->ske_cpu #define ke_assign ke_procq.tqe_next #define KEF_ASSIGNED KEF_SCHED0 /* KSE is being migrated. */ #define KEF_BOUND KEF_SCHED1 /* KSE can not migrate. */ struct kg_sched { int skg_slptime; /* Number of ticks we vol. slept */ int skg_runtime; /* Number of ticks we were running */ }; #define kg_slptime kg_sched->skg_slptime #define kg_runtime kg_sched->skg_runtime struct td_sched { int std_slptime; }; #define td_slptime td_sched->std_slptime struct td_sched td_sched; struct ke_sched ke_sched; struct kg_sched kg_sched; struct ke_sched *kse0_sched = &ke_sched; struct kg_sched *ksegrp0_sched = &kg_sched; struct p_sched *proc0_sched = NULL; struct td_sched *thread0_sched = &td_sched; /* * 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_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 kse belongs on the current or * next run queue. */ #define SCHED_INTERACTIVE(kg) \ (sched_interact_score(kg) < SCHED_INTERACT_THRESH) #define SCHED_CURR(kg, ke) \ (ke->ke_thread->td_priority != kg->kg_user_pri || \ SCHED_INTERACTIVE(kg)) /* * 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) /* * kseq - per processor runqs and statistics. */ #define KSEQ_NCLASS (PRI_IDLE + 1) /* Number of run classes. */ struct kseq { 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]; /* KSEs in each nice bin. */ short ksq_nicemin; /* Least nice. */ #ifdef SMP int ksq_load_transferable; /* kses that may be migrated. */ int ksq_idled; int ksq_cpus; /* Count of CPUs in this kseq. */ volatile struct kse *ksq_assigned; /* assigned by another CPU. */ #endif }; /* * One kse queue per processor. */ #ifdef SMP static int kseq_idle; static struct kseq kseq_cpu[MAXCPU]; static struct kseq *kseq_idmap[MAXCPU]; #define KSEQ_SELF() (kseq_idmap[PCPU_GET(cpuid)]) #define KSEQ_CPU(x) (kseq_idmap[(x)]) #else static struct kseq kseq_cpu; #define KSEQ_SELF() (&kseq_cpu) #define KSEQ_CPU(x) (&kseq_cpu) #endif static void sched_slice(struct kse *ke); static void sched_priority(struct ksegrp *kg); static int sched_interact_score(struct ksegrp *kg); static void sched_interact_update(struct ksegrp *kg); static void sched_interact_fork(struct ksegrp *kg); static void sched_pctcpu_update(struct kse *ke); /* Operations on per processor queues */ static struct kse * kseq_choose(struct kseq *kseq); static void kseq_setup(struct kseq *kseq); static void kseq_load_add(struct kseq *kseq, struct kse *ke); static void kseq_load_rem(struct kseq *kseq, struct kse *ke); static __inline void kseq_runq_add(struct kseq *kseq, struct kse *ke); static __inline void kseq_runq_rem(struct kseq *kseq, struct kse *ke); static void kseq_nice_add(struct kseq *kseq, int nice); static void kseq_nice_rem(struct kseq *kseq, int nice); void kseq_print(int cpu); #ifdef SMP static struct kse *runq_steal(struct runq *rq); static void sched_balance(void *arg); static void kseq_move(struct kseq *from, int cpu); static __inline void kseq_setidle(struct kseq *kseq); static void kseq_notify(struct kse *ke, int cpu); static void kseq_assign(struct kseq *); static struct kse *kseq_steal(struct kseq *kseq); #define KSE_CAN_MIGRATE(ke, class) \ ((class) != PRI_ITHD && (ke)->ke_thread->td_pinned == 0 && \ ((ke)->ke_flags & KEF_BOUND) == 0) #endif void kseq_print(int cpu) { struct kseq *kseq; int i; kseq = KSEQ_CPU(cpu); printf("kseq:\n"); printf("\tload: %d\n", kseq->ksq_load); printf("\tload TIMESHARE: %d\n", kseq->ksq_load_timeshare); #ifdef SMP printf("\tload transferable: %d\n", kseq->ksq_load_transferable); #endif printf("\tnicemin:\t%d\n", kseq->ksq_nicemin); printf("\tnice counts:\n"); for (i = 0; i < SCHED_PRI_NRESV; i++) if (kseq->ksq_nice[i]) printf("\t\t%d = %d\n", i - SCHED_PRI_NHALF, kseq->ksq_nice[i]); } static __inline void kseq_runq_add(struct kseq *kseq, struct kse *ke) { #ifdef SMP if (KSE_CAN_MIGRATE(ke, PRI_BASE(ke->ke_ksegrp->kg_pri_class))) kseq->ksq_load_transferable++; #endif runq_add(ke->ke_runq, ke); } static __inline void kseq_runq_rem(struct kseq *kseq, struct kse *ke) { #ifdef SMP if (KSE_CAN_MIGRATE(ke, PRI_BASE(ke->ke_ksegrp->kg_pri_class))) kseq->ksq_load_transferable--; #endif runq_remove(ke->ke_runq, ke); } static void kseq_load_add(struct kseq *kseq, struct kse *ke) { int class; mtx_assert(&sched_lock, MA_OWNED); class = PRI_BASE(ke->ke_ksegrp->kg_pri_class); if (class == PRI_TIMESHARE) kseq->ksq_load_timeshare++; kseq->ksq_load++; if (ke->ke_ksegrp->kg_pri_class == PRI_TIMESHARE) CTR6(KTR_ULE, "Add kse %p to %p (slice: %d, pri: %d, nice: %d(%d))", ke, ke->ke_runq, ke->ke_slice, ke->ke_thread->td_priority, ke->ke_ksegrp->kg_nice, kseq->ksq_nicemin); if (ke->ke_ksegrp->kg_pri_class == PRI_TIMESHARE) kseq_nice_add(kseq, ke->ke_ksegrp->kg_nice); } static void kseq_load_rem(struct kseq *kseq, struct kse *ke) { int class; mtx_assert(&sched_lock, MA_OWNED); class = PRI_BASE(ke->ke_ksegrp->kg_pri_class); if (class == PRI_TIMESHARE) kseq->ksq_load_timeshare--; kseq->ksq_load--; ke->ke_runq = NULL; if (ke->ke_ksegrp->kg_pri_class == PRI_TIMESHARE) kseq_nice_rem(kseq, ke->ke_ksegrp->kg_nice); } static void kseq_nice_add(struct kseq *kseq, int nice) { mtx_assert(&sched_lock, MA_OWNED); /* Normalize to zero. */ kseq->ksq_nice[nice + SCHED_PRI_NHALF]++; if (nice < kseq->ksq_nicemin || kseq->ksq_load_timeshare == 1) kseq->ksq_nicemin = nice; } static void kseq_nice_rem(struct kseq *kseq, int nice) { int n; mtx_assert(&sched_lock, MA_OWNED); /* Normalize to zero. */ n = nice + SCHED_PRI_NHALF; kseq->ksq_nice[n]--; KASSERT(kseq->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 != kseq->ksq_nicemin || kseq->ksq_nice[n] != 0 || kseq->ksq_load_timeshare == 0) return; for (; n < SCHED_PRI_NRESV; n++) if (kseq->ksq_nice[n]) { kseq->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 *arg) { struct kseq *kseq; int high_load; int low_load; int high_cpu; int low_cpu; int move; int diff; int i; high_cpu = 0; low_cpu = 0; high_load = 0; low_load = -1; mtx_lock_spin(&sched_lock); if (smp_started == 0) goto out; for (i = 0; i <= mp_maxid; i++) { if (CPU_ABSENT(i) || (i & stopped_cpus) != 0) continue; kseq = KSEQ_CPU(i); if (kseq->ksq_load_transferable > high_load) { high_load = kseq->ksq_load_transferable; high_cpu = i; } if (low_load == -1 || kseq->ksq_load < low_load) { low_load = kseq->ksq_load; low_cpu = i; } } kseq = KSEQ_CPU(high_cpu); /* * Nothing to do. */ if (high_load == 0 || low_load >= kseq->ksq_load) goto out; /* * Determine what the imbalance is and then adjust that to how many * kses we actually have to give up (load_transferable). */ diff = kseq->ksq_load - low_load; move = diff / 2; if (diff & 0x1) move++; move = min(move, high_load); for (i = 0; i < move; i++) kseq_move(kseq, low_cpu); out: mtx_unlock_spin(&sched_lock); callout_reset(&kseq_lb_callout, hz, sched_balance, NULL); return; } static void kseq_move(struct kseq *from, int cpu) { struct kse *ke; ke = kseq_steal(from); ke->ke_state = KES_THREAD; kseq_runq_rem(from, ke); kseq_load_rem(from, ke); ke->ke_cpu = cpu; kseq_notify(ke, cpu); } static __inline void kseq_setidle(struct kseq *kseq) { if (kseq->ksq_idled) return; kseq->ksq_idled = 1; atomic_set_int(&kseq_idle, PCPU_GET(cpumask)); return; } static void kseq_assign(struct kseq *kseq) { struct kse *nke; struct kse *ke; do { (volatile struct kse *)ke = kseq->ksq_assigned; } while(!atomic_cmpset_ptr(&kseq->ksq_assigned, ke, NULL)); for (; ke != NULL; ke = nke) { nke = ke->ke_assign; ke->ke_flags &= ~KEF_ASSIGNED; sched_add(ke->ke_thread); } } static void kseq_notify(struct kse *ke, int cpu) { struct kseq *kseq; struct thread *td; struct pcpu *pcpu; ke->ke_flags |= KEF_ASSIGNED; kseq = KSEQ_CPU(cpu); /* * Place a KSE on another cpu's queue and force a resched. */ do { (volatile struct kse *)ke->ke_assign = kseq->ksq_assigned; } while(!atomic_cmpset_ptr(&kseq->ksq_assigned, ke->ke_assign, ke)); pcpu = pcpu_find(cpu); td = pcpu->pc_curthread; if (ke->ke_thread->td_priority < td->td_priority || td == pcpu->pc_idlethread) { td->td_flags |= TDF_NEEDRESCHED; ipi_selected(1 << cpu, IPI_AST); } } static struct kse * runq_steal(struct runq *rq) { struct rqhead *rqh; struct rqbits *rqb; struct kse *ke; 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] & (1 << bit)) == 0) continue; rqh = &rq->rq_queues[bit + (word << RQB_L2BPW)]; TAILQ_FOREACH(ke, rqh, ke_procq) { if (KSE_CAN_MIGRATE(ke, PRI_BASE(ke->ke_ksegrp->kg_pri_class))) return (ke); } } } return (NULL); } static struct kse * kseq_steal(struct kseq *kseq) { struct kse *ke; if ((ke = runq_steal(kseq->ksq_curr)) != NULL) return (ke); if ((ke = runq_steal(kseq->ksq_next)) != NULL) return (ke); return (runq_steal(&kseq->ksq_idle)); } #endif /* SMP */ /* * Pick the highest priority task we have and return it. */ static struct kse * kseq_choose(struct kseq *kseq) { struct kse *ke; struct runq *swap; mtx_assert(&sched_lock, MA_OWNED); swap = NULL; for (;;) { ke = runq_choose(kseq->ksq_curr); if (ke == NULL) { /* * We already swaped once and didn't get anywhere. */ if (swap) break; swap = kseq->ksq_curr; kseq->ksq_curr = kseq->ksq_next; kseq->ksq_next = swap; continue; } /* * If we encounter a slice of 0 the kse is in a * TIMESHARE kse group and its nice was too far out * of the range that receives slices. */ if (ke->ke_slice == 0) { runq_remove(ke->ke_runq, ke); sched_slice(ke); ke->ke_runq = kseq->ksq_next; runq_add(ke->ke_runq, ke); continue; } return (ke); } return (runq_choose(&kseq->ksq_idle)); } static void kseq_setup(struct kseq *kseq) { runq_init(&kseq->ksq_timeshare[0]); runq_init(&kseq->ksq_timeshare[1]); runq_init(&kseq->ksq_idle); kseq->ksq_curr = &kseq->ksq_timeshare[0]; kseq->ksq_next = &kseq->ksq_timeshare[1]; kseq->ksq_load = 0; kseq->ksq_load_timeshare = 0; #ifdef SMP kseq->ksq_load_transferable = 0; kseq->ksq_idled = 0; kseq->ksq_assigned = NULL; #endif } static void sched_setup(void *dummy) { #ifdef SMP int i; #endif slice_min = (hz/100); /* 10ms */ slice_max = (hz/7); /* ~140ms */ #ifdef SMP /* init kseqs */ /* Create the idmap. */ #ifdef ULE_HTT_EXPERIMENTAL if (smp_topology == NULL) { #else if (1) { #endif for (i = 0; i < MAXCPU; i++) { kseq_setup(&kseq_cpu[i]); kseq_idmap[i] = &kseq_cpu[i]; kseq_cpu[i].ksq_cpus = 1; } } else { int j; for (i = 0; i < smp_topology->ct_count; i++) { struct cpu_group *cg; cg = &smp_topology->ct_group[i]; kseq_setup(&kseq_cpu[i]); for (j = 0; j < MAXCPU; j++) if ((cg->cg_mask & (1 << j)) != 0) kseq_idmap[j] = &kseq_cpu[i]; kseq_cpu[i].ksq_cpus = cg->cg_count; } } callout_init(&kseq_lb_callout, CALLOUT_MPSAFE); sched_balance(NULL); #else kseq_setup(KSEQ_SELF()); #endif mtx_lock_spin(&sched_lock); kseq_load_add(KSEQ_SELF(), &kse0); mtx_unlock_spin(&sched_lock); } /* * Scale the scheduling priority according to the "interactivity" of this * process. */ static void sched_priority(struct ksegrp *kg) { int pri; if (kg->kg_pri_class != PRI_TIMESHARE) return; pri = SCHED_PRI_INTERACT(sched_interact_score(kg)); pri += SCHED_PRI_BASE; pri += kg->kg_nice; if (pri > PRI_MAX_TIMESHARE) pri = PRI_MAX_TIMESHARE; else if (pri < PRI_MIN_TIMESHARE) pri = PRI_MIN_TIMESHARE; kg->kg_user_pri = pri; return; } /* * Calculate a time slice based on the properties of the kseg and the runq * that we're on. This is only for PRI_TIMESHARE ksegrps. */ static void sched_slice(struct kse *ke) { struct kseq *kseq; struct ksegrp *kg; kg = ke->ke_ksegrp; kseq = KSEQ_CPU(ke->ke_cpu); /* * Rationale: * KSEs in interactive ksegs get the minimum slice so that we * quickly notice if it abuses its advantage. * * KSEs in non-interactive ksegs are assigned a slice that is * based on the ksegs nice value relative to the least nice kseg * on the run queue for this cpu. * * If the KSE is less nice than all others it gets the maximum * slice and other KSEs will adjust their slice relative to * this when they first expire. * * There is 20 point window that starts relative to the least * nice kse on the run queue. Slice size is determined by * the kse distance from the last nice ksegrp. * * If the kse 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 ksegs when * a nice -20 is running. They are always granted a minimum * slice. */ if (!SCHED_INTERACTIVE(kg)) { int nice; nice = kg->kg_nice + (0 - kseq->ksq_nicemin); if (kseq->ksq_load_timeshare == 0 || kg->kg_nice < kseq->ksq_nicemin) ke->ke_slice = SCHED_SLICE_MAX; else if (nice <= SCHED_SLICE_NTHRESH) ke->ke_slice = SCHED_SLICE_NICE(nice); else if (kg->kg_nice == 0) ke->ke_slice = SCHED_SLICE_MIN; else ke->ke_slice = 0; } else ke->ke_slice = SCHED_SLICE_MIN; CTR6(KTR_ULE, "Sliced %p(%d) (nice: %d, nicemin: %d, load: %d, interactive: %d)", ke, ke->ke_slice, kg->kg_nice, kseq->ksq_nicemin, kseq->ksq_load_timeshare, SCHED_INTERACTIVE(kg)); 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 ksegrp *kg) { int sum; sum = kg->kg_runtime + kg->kg_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 [3/5 * SCHED_INTERACT_MAX, SCHED_INTERACT_MAX] */ if (sum > (SCHED_INTERACT_MAX / 5) * 6) { kg->kg_runtime /= 2; kg->kg_slptime /= 2; return; } kg->kg_runtime = (kg->kg_runtime / 5) * 4; kg->kg_slptime = (kg->kg_slptime / 5) * 4; } static void sched_interact_fork(struct ksegrp *kg) { int ratio; int sum; sum = kg->kg_runtime + kg->kg_slptime; if (sum > SCHED_SLP_RUN_FORK) { ratio = sum / SCHED_SLP_RUN_FORK; kg->kg_runtime /= ratio; kg->kg_slptime /= ratio; } } static int sched_interact_score(struct ksegrp *kg) { int div; if (kg->kg_runtime > kg->kg_slptime) { div = max(1, kg->kg_runtime / SCHED_INTERACT_HALF); return (SCHED_INTERACT_HALF + (SCHED_INTERACT_HALF - (kg->kg_slptime / div))); } if (kg->kg_slptime > kg->kg_runtime) { div = max(1, kg->kg_slptime / SCHED_INTERACT_HALF); return (kg->kg_runtime / div); } /* * This can happen if slptime and runtime are 0. */ return (0); } /* * 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 kse *ke) { /* * Adjust counters and watermark for pctcpu calc. */ if (ke->ke_ltick > ticks - SCHED_CPU_TICKS) { /* * Shift the tick count out so that the divide doesn't * round away our results. */ ke->ke_ticks <<= 10; ke->ke_ticks = (ke->ke_ticks / (ticks - ke->ke_ftick)) * SCHED_CPU_TICKS; ke->ke_ticks >>= 10; } else ke->ke_ticks = 0; ke->ke_ltick = ticks; ke->ke_ftick = ke->ke_ltick - SCHED_CPU_TICKS; } void sched_prio(struct thread *td, u_char prio) { struct kse *ke; ke = td->td_kse; mtx_assert(&sched_lock, MA_OWNED); 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 && ke && (ke->ke_flags & KEF_ASSIGNED) == 0 && ke->ke_runq != KSEQ_CPU(ke->ke_cpu)->ksq_curr) { runq_remove(ke->ke_runq, ke); ke->ke_runq = KSEQ_CPU(ke->ke_cpu)->ksq_curr; runq_add(ke->ke_runq, ke); } adjustrunqueue(td, prio); } else td->td_priority = prio; } void sched_switch(struct thread *td) { struct thread *newtd; struct kse *ke; mtx_assert(&sched_lock, MA_OWNED); ke = td->td_kse; td->td_last_kse = ke; td->td_lastcpu = td->td_oncpu; td->td_oncpu = NOCPU; td->td_flags &= ~TDF_NEEDRESCHED; if (TD_IS_RUNNING(td)) { if (td->td_proc->p_flag & P_SA) { kseq_load_rem(KSEQ_CPU(ke->ke_cpu), ke); setrunqueue(td); } else { /* * This queue is always correct except for idle threads * which have a higher priority due to priority * propagation. */ if (ke->ke_ksegrp->kg_pri_class == PRI_IDLE) { if (td->td_priority < PRI_MIN_IDLE) ke->ke_runq = KSEQ_SELF()->ksq_curr; else ke->ke_runq = &KSEQ_SELF()->ksq_idle; } kseq_runq_add(KSEQ_SELF(), ke); } } else { if (ke->ke_runq) kseq_load_rem(KSEQ_CPU(ke->ke_cpu), ke); /* * We will not be on the run queue. So we must be * sleeping or similar. */ if (td->td_proc->p_flag & P_SA) kse_reassign(ke); } newtd = choosethread(); if (td != newtd) cpu_switch(td, newtd); sched_lock.mtx_lock = (uintptr_t)td; td->td_oncpu = PCPU_GET(cpuid); } void sched_nice(struct ksegrp *kg, int nice) { struct kse *ke; struct thread *td; struct kseq *kseq; PROC_LOCK_ASSERT(kg->kg_proc, MA_OWNED); mtx_assert(&sched_lock, MA_OWNED); /* * We need to adjust the nice counts for running KSEs. */ if (kg->kg_pri_class == PRI_TIMESHARE) FOREACH_KSE_IN_GROUP(kg, ke) { if (ke->ke_runq == NULL) continue; kseq = KSEQ_CPU(ke->ke_cpu); kseq_nice_rem(kseq, kg->kg_nice); kseq_nice_add(kseq, nice); } kg->kg_nice = nice; sched_priority(kg); FOREACH_THREAD_IN_GROUP(kg, td) td->td_flags |= TDF_NEEDRESCHED; } void sched_sleep(struct thread *td, u_char prio) { mtx_assert(&sched_lock, MA_OWNED); td->td_slptime = ticks; td->td_priority = prio; CTR2(KTR_ULE, "sleep kse %p (tick: %d)", td->td_kse, td->td_slptime); } void sched_wakeup(struct thread *td) { mtx_assert(&sched_lock, MA_OWNED); /* * Let the kseg know how long we slept for. This is because process * interactivity behavior is modeled in the kseg. */ if (td->td_slptime) { struct ksegrp *kg; int hzticks; kg = td->td_ksegrp; hzticks = (ticks - td->td_slptime) << 10; if (hzticks >= SCHED_SLP_RUN_MAX) { kg->kg_slptime = SCHED_SLP_RUN_MAX; kg->kg_runtime = 1; } else { kg->kg_slptime += hzticks; sched_interact_update(kg); } sched_priority(kg); if (td->td_kse) sched_slice(td->td_kse); CTR2(KTR_ULE, "wakeup kse %p (%d ticks)", td->td_kse, hzticks); td->td_slptime = 0; } setrunqueue(td); } /* * Penalize the parent for creating a new child and initialize the child's * priority. */ void sched_fork(struct proc *p, struct proc *p1) { mtx_assert(&sched_lock, MA_OWNED); sched_fork_ksegrp(FIRST_KSEGRP_IN_PROC(p), FIRST_KSEGRP_IN_PROC(p1)); sched_fork_kse(FIRST_KSE_IN_PROC(p), FIRST_KSE_IN_PROC(p1)); sched_fork_thread(FIRST_THREAD_IN_PROC(p), FIRST_THREAD_IN_PROC(p1)); } void sched_fork_kse(struct kse *ke, struct kse *child) { child->ke_slice = 1; /* Attempt to quickly learn interactivity. */ child->ke_cpu = ke->ke_cpu; child->ke_runq = NULL; /* Grab our parents cpu estimation information. */ child->ke_ticks = ke->ke_ticks; child->ke_ltick = ke->ke_ltick; child->ke_ftick = ke->ke_ftick; } void sched_fork_ksegrp(struct ksegrp *kg, struct ksegrp *child) { PROC_LOCK_ASSERT(child->kg_proc, MA_OWNED); child->kg_slptime = kg->kg_slptime; child->kg_runtime = kg->kg_runtime; child->kg_user_pri = kg->kg_user_pri; child->kg_nice = kg->kg_nice; sched_interact_fork(child); kg->kg_runtime += tickincr << 10; sched_interact_update(kg); CTR6(KTR_ULE, "sched_fork_ksegrp: %d(%d, %d) - %d(%d, %d)", kg->kg_proc->p_pid, kg->kg_slptime, kg->kg_runtime, child->kg_proc->p_pid, child->kg_slptime, child->kg_runtime); } void sched_fork_thread(struct thread *td, struct thread *child) { } void sched_class(struct ksegrp *kg, int class) { struct kseq *kseq; struct kse *ke; int nclass; int oclass; mtx_assert(&sched_lock, MA_OWNED); if (kg->kg_pri_class == class) return; nclass = PRI_BASE(class); oclass = PRI_BASE(kg->kg_pri_class); FOREACH_KSE_IN_GROUP(kg, ke) { if (ke->ke_state != KES_ONRUNQ && ke->ke_state != KES_THREAD) continue; kseq = KSEQ_CPU(ke->ke_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 (ke->ke_state == KES_ONRUNQ) { if (KSE_CAN_MIGRATE(ke, oclass)) kseq->ksq_load_transferable--; if (KSE_CAN_MIGRATE(ke, nclass)) kseq->ksq_load_transferable++; } #endif if (oclass == PRI_TIMESHARE) { kseq->ksq_load_timeshare--; kseq_nice_rem(kseq, kg->kg_nice); } if (nclass == PRI_TIMESHARE) { kseq->ksq_load_timeshare++; kseq_nice_add(kseq, kg->kg_nice); } } kg->kg_pri_class = class; } /* * Return some of the child's priority and interactivity to the parent. */ void sched_exit(struct proc *p, struct proc *child) { mtx_assert(&sched_lock, MA_OWNED); sched_exit_kse(FIRST_KSE_IN_PROC(p), FIRST_KSE_IN_PROC(child)); sched_exit_ksegrp(FIRST_KSEGRP_IN_PROC(p), FIRST_KSEGRP_IN_PROC(child)); } void sched_exit_kse(struct kse *ke, struct kse *child) { kseq_load_rem(KSEQ_CPU(child->ke_cpu), child); } void sched_exit_ksegrp(struct ksegrp *kg, struct ksegrp *child) { /* kg->kg_slptime += child->kg_slptime; */ kg->kg_runtime += child->kg_runtime; sched_interact_update(kg); } void sched_exit_thread(struct thread *td, struct thread *child) { } void sched_clock(struct thread *td) { struct kseq *kseq; struct ksegrp *kg; struct kse *ke; /* * sched_setup() apparently happens prior to stathz being set. We * need to resolve the timers earlier in the boot so we can avoid * calculating this here. */ if (realstathz == 0) { realstathz = stathz ? stathz : hz; tickincr = hz / realstathz; /* * XXX This does not work for values of stathz that are much * larger than hz. */ if (tickincr == 0) tickincr = 1; } ke = td->td_kse; kg = ke->ke_ksegrp; mtx_assert(&sched_lock, MA_OWNED); KASSERT((td != NULL), ("schedclock: null thread pointer")); /* Adjust ticks for pctcpu */ ke->ke_ticks++; ke->ke_ltick = ticks; /* Go up to one second beyond our max and then trim back down */ if (ke->ke_ftick + SCHED_CPU_TICKS + hz < ke->ke_ltick) sched_pctcpu_update(ke); if (td->td_flags & TDF_IDLETD) return; CTR4(KTR_ULE, "Tick kse %p (slice: %d, slptime: %d, runtime: %d)", ke, ke->ke_slice, kg->kg_slptime >> 10, kg->kg_runtime >> 10); /* * We only do slicing code for TIMESHARE ksegrps. */ if (kg->kg_pri_class != PRI_TIMESHARE) return; /* * We used a tick charge it to the ksegrp so that we can compute our * interactivity. */ kg->kg_runtime += tickincr << 10; sched_interact_update(kg); /* * We used up one time slice. */ if (--ke->ke_slice > 0) return; /* * We're out of time, recompute priorities and requeue. */ kseq = KSEQ_SELF(); kseq_load_rem(kseq, ke); sched_priority(kg); sched_slice(ke); if (SCHED_CURR(kg, ke)) ke->ke_runq = kseq->ksq_curr; else ke->ke_runq = kseq->ksq_next; kseq_load_add(kseq, ke); td->td_flags |= TDF_NEEDRESCHED; } int sched_runnable(void) { struct kseq *kseq; int load; load = 1; kseq = KSEQ_SELF(); #ifdef SMP if (kseq->ksq_assigned) { mtx_lock_spin(&sched_lock); kseq_assign(kseq); mtx_unlock_spin(&sched_lock); } #endif if ((curthread->td_flags & TDF_IDLETD) != 0) { if (kseq->ksq_load > 0) goto out; } else if (kseq->ksq_load - 1 > 0) goto out; load = 0; out: return (load); } void sched_userret(struct thread *td) { struct ksegrp *kg; kg = td->td_ksegrp; if (td->td_priority != kg->kg_user_pri) { mtx_lock_spin(&sched_lock); td->td_priority = kg->kg_user_pri; mtx_unlock_spin(&sched_lock); } } struct kse * sched_choose(void) { struct kseq *kseq; struct kse *ke; mtx_assert(&sched_lock, MA_OWNED); kseq = KSEQ_SELF(); #ifdef SMP if (kseq->ksq_assigned) kseq_assign(kseq); #endif ke = kseq_choose(kseq); if (ke) { #ifdef SMP if (ke->ke_ksegrp->kg_pri_class == PRI_IDLE) kseq_setidle(kseq); #endif kseq_runq_rem(kseq, ke); ke->ke_state = KES_THREAD; if (ke->ke_ksegrp->kg_pri_class == PRI_TIMESHARE) { CTR4(KTR_ULE, "Run kse %p from %p (slice: %d, pri: %d)", ke, ke->ke_runq, ke->ke_slice, ke->ke_thread->td_priority); } return (ke); } #ifdef SMP kseq_setidle(kseq); #endif return (NULL); } void sched_add(struct thread *td) { struct kseq *kseq; struct ksegrp *kg; struct kse *ke; int class; mtx_assert(&sched_lock, MA_OWNED); ke = td->td_kse; kg = td->td_ksegrp; if (ke->ke_flags & KEF_ASSIGNED) return; kseq = KSEQ_SELF(); KASSERT((ke->ke_thread != NULL), ("sched_add: No thread on KSE")); KASSERT((ke->ke_thread->td_kse != NULL), ("sched_add: No KSE on thread")); KASSERT(ke->ke_state != KES_ONRUNQ, ("sched_add: kse %p (%s) already in run queue", ke, ke->ke_proc->p_comm)); KASSERT(ke->ke_proc->p_sflag & PS_INMEM, ("sched_add: process swapped out")); KASSERT(ke->ke_runq == NULL, ("sched_add: KSE %p is still assigned to a run queue", ke)); class = PRI_BASE(kg->kg_pri_class); switch (class) { case PRI_ITHD: case PRI_REALTIME: ke->ke_runq = kseq->ksq_curr; ke->ke_slice = SCHED_SLICE_MAX; ke->ke_cpu = PCPU_GET(cpuid); break; case PRI_TIMESHARE: #ifdef SMP if (ke->ke_cpu != PCPU_GET(cpuid)) { kseq_notify(ke, ke->ke_cpu); return; } #endif if (SCHED_CURR(kg, ke)) ke->ke_runq = kseq->ksq_curr; else ke->ke_runq = kseq->ksq_next; break; case PRI_IDLE: #ifdef SMP if (ke->ke_cpu != PCPU_GET(cpuid)) { kseq_notify(ke, ke->ke_cpu); return; } #endif /* * This is for priority prop. */ if (ke->ke_thread->td_priority < PRI_MIN_IDLE) ke->ke_runq = kseq->ksq_curr; else ke->ke_runq = &kseq->ksq_idle; ke->ke_slice = SCHED_SLICE_MIN; break; default: panic("Unknown pri class."); break; } #ifdef SMP /* * If there are any idle processors, give them our extra load. 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 swiches. */ if (kseq->ksq_load_transferable > kseq->ksq_cpus && KSE_CAN_MIGRATE(ke, class) && kseq_idle) { int cpu; /* * Multiple cpus could find this bit simultaneously but the * race shouldn't be terrible. */ cpu = ffs(kseq_idle); if (cpu) { cpu--; atomic_clear_int(&kseq_idle, 1 << cpu); ke->ke_cpu = cpu; ke->ke_runq = NULL; kseq_notify(ke, cpu); return; } } if (kseq->ksq_idled && (class == PRI_TIMESHARE || class == PRI_REALTIME)) { atomic_clear_int(&kseq_idle, PCPU_GET(cpumask)); kseq->ksq_idled = 0; } #endif if (td->td_priority < curthread->td_priority) curthread->td_flags |= TDF_NEEDRESCHED; ke->ke_ksegrp->kg_runq_kses++; ke->ke_state = KES_ONRUNQ; kseq_runq_add(kseq, ke); kseq_load_add(kseq, ke); } void sched_rem(struct thread *td) { struct kseq *kseq; struct kse *ke; ke = td->td_kse; /* * It is safe to just return here because sched_rem() is only ever * used in places where we're immediately going to add the * kse back on again. In that case it'll be added with the correct * thread and priority when the caller drops the sched_lock. */ if (ke->ke_flags & KEF_ASSIGNED) return; mtx_assert(&sched_lock, MA_OWNED); KASSERT((ke->ke_state == KES_ONRUNQ), ("KSE not on run queue")); ke->ke_state = KES_THREAD; ke->ke_ksegrp->kg_runq_kses--; kseq = KSEQ_CPU(ke->ke_cpu); kseq_runq_rem(kseq, ke); kseq_load_rem(kseq, ke); } fixpt_t sched_pctcpu(struct thread *td) { fixpt_t pctcpu; struct kse *ke; pctcpu = 0; ke = td->td_kse; if (ke == NULL) return (0); mtx_lock_spin(&sched_lock); if (ke->ke_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 (ke->ke_ltick < (ticks - (hz / 2))) sched_pctcpu_update(ke); /* How many rtick per second ? */ rtick = min(ke->ke_ticks / SCHED_CPU_TIME, SCHED_CPU_TICKS); pctcpu = (FSCALE * ((FSCALE * rtick)/realstathz)) >> FSHIFT; } ke->ke_proc->p_swtime = ke->ke_ltick - ke->ke_ftick; mtx_unlock_spin(&sched_lock); return (pctcpu); } void sched_bind(struct thread *td, int cpu) { struct kse *ke; mtx_assert(&sched_lock, MA_OWNED); ke = td->td_kse; #ifndef SMP ke->ke_flags |= KEF_BOUND; #else if (PCPU_GET(cpuid) == cpu) { ke->ke_flags |= KEF_BOUND; return; } /* sched_rem without the runq_remove */ ke->ke_state = KES_THREAD; ke->ke_ksegrp->kg_runq_kses--; kseq_load_rem(KSEQ_CPU(ke->ke_cpu), ke); ke->ke_cpu = cpu; kseq_notify(ke, cpu); /* When we return from mi_switch we'll be on the correct cpu. */ td->td_proc->p_stats->p_ru.ru_nvcsw++; mi_switch(); #endif } void sched_unbind(struct thread *td) { mtx_assert(&sched_lock, MA_OWNED); td->td_kse->ke_flags &= ~KEF_BOUND; } int sched_sizeof_kse(void) { return (sizeof(struct kse) + sizeof(struct ke_sched)); } int sched_sizeof_ksegrp(void) { return (sizeof(struct ksegrp) + sizeof(struct kg_sched)); } int sched_sizeof_proc(void) { return (sizeof(struct proc)); } int sched_sizeof_thread(void) { return (sizeof(struct thread) + sizeof(struct td_sched)); }