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add mismatch and fallback counters

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This commit is contained in:
Charlie Root 2019-08-31 14:54:51 -04:00
parent caba92060d
commit 21aa3325fc
3 changed files with 82 additions and 32 deletions
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98
sys/kern/kern_event.c
View File

@ -89,8 +89,8 @@ __FBSDID("$FreeBSD$");
static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system");
#define KQDOM_FLAGS (KQ_SCHED_CPU | KQ_SCHED_QUEUE)
#define KEVQ_LAT_FLAGS (KQ_SCHED_CPU | KQ_SCHED_QUEUE | KQ_SCHED_BEST)
#define KEVQ_LAT_FLAGS ((uint64_t)-1) //(KQ_SCHED_CPU | KQ_SCHED_QUEUE | KQ_SCHED_BEST)
#define DUMP_INDENT (4)
/*
* This lock is used if multiple kq locks are required. This possibly
* should be made into a per proc lock.
@ -112,11 +112,13 @@ TASKQUEUE_DEFINE_THREAD(kqueue_ctx);
// TODO: only use it in SMP
extern struct cpu_group *cpu_top;
#define AVG_WEIGHT_FACTOR_OLD (4)
#define AVG_WEIGHT_FACTOR_NEW (1)
/* no need to handle overflow as long as the existing org/cur doesn't overflow */
#define CALC_OVERTIME_AVG(prev, cur) (((prev) * AVG_WEIGHT_FACTOR_OLD + (cur) * AVG_WEIGHT_FACTOR_NEW) / (AVG_WEIGHT_FACTOR_OLD + AVG_WEIGHT_FACTOR_NEW))
static inline uint64_t
calc_overtime_avg(uint64_t prev, uint64_t cur, uint32_t prev_pct)
{
KASSERT(prev_pct < 100, ("overtime average prev_pct >= 100"));
return (prev * prev_pct + cur * (100 - prev_pct)) / 100;
}
static struct kevq * kevqlist_find(struct kevqlist *kevq_list, struct kqueue *kq);
static void kevq_thred_init(struct kevq_thred *kevq_th);
@ -127,7 +129,7 @@ static void kevq_release(struct kevq* kevq, int locked);
static void kevq_destroy(struct kevq *kevq);
static int kevq_acquire(struct kevq *kevq, int locked);
static void kevq_worksteal(struct kevq *kevq);
void kevq_drain(struct kevq *kevq, struct thread *td);
static void kevq_drain(struct kevq *kevq, struct thread *td);
static void kevq_activate(struct kevq *kevq, struct thread *td);
@ -1474,13 +1476,14 @@ kqueue_kevent(struct kqueue *kq, struct kevq *kevq, struct thread *td, int nchan
CTR3(KTR_KQ, "kevent: td %d nkev %d kevent (delta) %ld ns", td->td_tid, kevq->kevq_last_nkev, cur_ts);
/* divide by the number of events processed */
/* update total time */
kevq->kevq_tot_time += cur_ts;
/* update average latency */
avg = cur_ts / kevq->kevq_last_nkev;
CTR3(KTR_KQ, "kevent: td %d nkev %d kevent (avg) %ld ns", td->td_tid, kevq->kevq_last_nkev, avg);
if (kevq->kevq_avg_lat != 0) {
kevq->kevq_avg_lat = CALC_OVERTIME_AVG(kevq->kevq_avg_lat, avg);
kevq->kevq_avg_lat = calc_overtime_avg(kevq->kevq_avg_lat, avg, 80);
} else {
kevq->kevq_avg_lat = avg;
}
@ -2339,7 +2342,26 @@ kqdom_destroy(struct kqdom *root)
static void
kevq_dump(struct kevq *kevq, int level, struct sbuf *buf)
{
sbuf_printf(buf, "%*c<kevq: %p #knotes: %d avg_lat: %ld/>\n", level * 2, ' ', kevq, kevq->kn_count, kevq->kevq_avg_lat);
int error;
error = sbuf_printf(buf, "%*c<kevq: %p knotes: %d "
"total_time: %ld "
"total_syscall: %ld "
"total_events: %ld "
"avg_latency: %ld "
"avg_events: %ld "
"total_fallbacks: %ld "
"total_mismatches: %ld/>\n",
level * DUMP_INDENT, ' ', kevq, kevq->kn_count,
kevq->kevq_tot_time,
kevq->kevq_tot_syscall,
kevq->kevq_tot_ev,
kevq->kevq_avg_lat,
kevq->kevq_avg_ev,
kevq->kevq_tot_fallback,
kevq->kevq_tot_kqd_mismatch);
KASSERT(error == 0, ("error writing sbuf"));
}
static void
@ -2347,10 +2369,8 @@ kqdom_dump(struct kqdom *kqd, int level, struct sbuf *buf)
{
/* XXX: No potential race between this and kqdom_build() for now.
* If we move kqdom_build() out of kqueue() syscall then there is a potential race */
/* XXX2: check return code */
sbuf_printf(buf, "%*c<kqdom id: %d level: %d cpu_mask:0x%lx #children: %d #active: %d leaf: %d #kevq: %d>\n", level * 2, ' ',
int error;
error = sbuf_printf(buf, "%*c<kqdom id: %d level: %d cpu_mask:0x%lx #children: %d #active: %d leaf: %d #kevq: %d>\n", level * DUMP_INDENT, ' ',
kqd->id,
level,
kqd->cpu_mask.__bits[0],
@ -2358,11 +2378,12 @@ kqdom_dump(struct kqdom *kqd, int level, struct sbuf *buf)
veclist_size(&kqd->kqd_activelist),
kqdom_is_leaf(kqd),
veclist_size(&kqd->kqd_kevqs));
KASSERT(error == 0, ("error writing sbuf"));
if (kqdom_is_leaf(kqd)) {
KQD_RLOCK(kqd);
/* print all kevqs */
for (int i = 0; i < veclist_size(&kqd->kqd_kevqs); i++) {
/* XXX: check return code */
kevq_dump(veclist_at(&kqd->kqd_kevqs, i), level + 1, buf);
}
KQD_RUNLOCK(kqd);
@ -2371,9 +2392,8 @@ kqdom_dump(struct kqdom *kqd, int level, struct sbuf *buf)
kqdom_dump(veclist_at(&kqd->children, i), level + 1, buf);
}
}
/* XXX: check return code */
sbuf_printf(buf, "%*c</kqdom>\n", level * 2, ' ');
error = sbuf_printf(buf, "%*c</kqdom>\n", level * DUMP_INDENT, ' ');
KASSERT(error == 0, ("error writing sbuf"));
}
@ -2440,7 +2460,7 @@ kqdom_update_lat(struct kqdom *leaf, uint64_t avg)
while(leaf != NULL) {
if (leaf->avg_lat != 0) {
// bit rot race here?
leaf->avg_lat = CALC_OVERTIME_AVG(leaf->avg_lat, avg);
leaf->avg_lat = calc_overtime_avg(leaf->avg_lat, avg, 80);
} else {
leaf->avg_lat = avg;
}
@ -3005,11 +3025,20 @@ kqueue_scan(struct kevq *kevq, int maxevents, struct kevent_copyops *k_ops,
KEVQ_UNLOCK(kevq);
if (nkev != 0 && (KQSCHED_GET_SCHED(kq) & KEVQ_LAT_FLAGS)) {
if (nkev > 0 && (KQSCHED_GET_SCHED(kq) & KEVQ_LAT_FLAGS)) {
/* book keep the statistics */
kevq->kevq_last_kev = get_cyclecount();
kevq->kevq_last_nkev = nkev;
CTR3(KTR_KQ, "kevent: td %d nkev %d kevent (exit) %ld ns", td->td_tid, kevq->kevq_last_nkev, kevq->kevq_last_kev);
/* update total ev */
kevq->kevq_tot_ev += nkev;
kevq->kevq_tot_syscall++;
if (kevq->kevq_avg_ev == 0) {
kevq->kevq_avg_ev = nkev;
} else {
kevq->kevq_avg_ev = calc_overtime_avg(kevq->kevq_avg_ev, nkev, 80);
}
}
CTR2(KTR_KQ, "kqueue_scan: knote_free marker %p td %d", marker, td->td_tid);
@ -3099,11 +3128,11 @@ kqueue_ioctl(struct file *fp, u_long cmd, void *data,
if (kq->kq_flags & KQ_FLAG_MULTI) {
/* 4MB buffer */
dat = malloc(sizeof(char) * 4096 * 1024, M_KQUEUE, M_WAITOK | M_ZERO);
sbuf_new(&buf, dat, 4096 * 1024 * sizeof(char), SBUF_AUTOEXTEND | SBUF_INCLUDENUL);
sbuf_new(&buf, dat, 4096 * 1024 * sizeof(char), SBUF_INCLUDENUL);
/* dump kvlst */
/* XXX: check return status of sbuf_printf */
sbuf_printf(&buf, "KQ 0x%p dump:\n\nActive KEVQ:\n", kq);
error = sbuf_printf(&buf, "KQ 0x%p dump:\n\nActive KEVQ:\n", kq);
KASSERT(error == 0, ("error writing sbuf"));
KVLST_RLOCK(kq);
for(int i = 0; i < veclist_size(&kq->kevq_vlist); i++) {
kevq_dump(veclist_at(&kq->kevq_vlist, i), 0, &buf);
@ -3112,11 +3141,13 @@ kqueue_ioctl(struct file *fp, u_long cmd, void *data,
/* dump kqdom if used */
if (KQSCHED_GET_SCHED(kq) & KQDOM_FLAGS) {
sbuf_printf(&buf, "\nKQDOM:\n");
error = sbuf_printf(&buf, "\nKQDOM:\n");
KASSERT(error == 0, ("error writing sbuf"));
kqdom_dump(kq->kq_kqd, 0, &buf);
}
sbuf_finish(&buf);
error = sbuf_finish(&buf);
KASSERT(error == 0, ("error sbuf_finish"));
uprintf("%s", sbuf_data(&buf));
sbuf_delete(&buf);
free(dat, M_KQUEUE);
@ -4141,7 +4172,9 @@ knote_next_kevq(struct knote *kn)
int sargs;
int sched;
int rand, sz;
int kqd_mismatch;
kqd_mismatch = 0;
next_kevq = NULL;
kq = kn->kn_kq;
sargs = KQSCHED_GET_SARGS(kq);
@ -4180,10 +4213,14 @@ knote_next_kevq(struct knote *kn)
kn->kn_kqd = kqdom_find(kq->kq_kqd, PCPU_GET(cpuid));
KASSERT(kn->kn_kqd != NULL, ("knote scheduled on an unidentified CPU"));
CTR3(KTR_KQ, "knote_next_kevq: [QUEUE%d] knote %p attached to kqdom id %d", sargs, kn, kn->kn_kqd->id);
CTR4(KTR_KQ, "knote_next_kevq: [QUEUE%d] knote %p attached to kqdom id %d cpuset 0x%lx", sargs, kn, kn->kn_kqd->id, kn->kn_kqd->cpu_mask.__bits[0]);
}
kqd = kn->kn_kqd;
/* Check if the knote interrupt is triggered on a cpu that's different from the memorized one */
if (!CPU_ISSET(PCPU_GET(cpuid), &kqd->cpu_mask)) {
kqd_mismatch = 1;
}
done_cq:
KASSERT(kqdom_is_leaf(kqd), ("found kqdom not leaf"));
@ -4203,6 +4240,10 @@ knote_next_kevq(struct knote *kn)
next_kevq = kevq_lock_check_avail(next_kevq);
KQD_RUNLOCK(kqd);
if (kqd_mismatch && next_kevq != NULL) {
next_kevq->kevq_tot_kqd_mismatch++;
}
CTR3(KTR_KQ, "knote_next_kevq: [QUEUE/CPU%d] next kevq %p for kn %p", sargs, next_kevq, kn);
break;
@ -4232,6 +4273,7 @@ knote_next_kevq(struct knote *kn)
next_kevq = kevq_lock_check_avail(next_kevq);
if (next_kevq != NULL) {
next_kevq->kevq_tot_fallback++;
break;
}

12
sys/sys/eventvar.h
View File

@ -65,10 +65,18 @@ struct kevq {
int kevq_state;
int kevq_refcnt;
/* Used by the scheduler */
uint64_t kevq_avg_lat;
uint64_t kevq_last_kev;
uint64_t kevq_last_nkev;
/* Sched stats */
uint64_t kevq_avg_lat;
uint64_t kevq_avg_ev;
uint64_t kevq_tot_ev;
uint64_t kevq_tot_time;
uint64_t kevq_tot_syscall;
/* TODO: maybe these should be in kqdomain or global */
uint64_t kevq_tot_fallback;
uint64_t kevq_tot_kqd_mismatch;
};
/* TODO: assumed that threads don't get rescheduled across cores */