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add cap to workstealing controlled by sysctl and its stat dumps

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This commit is contained in:
Oscar Zhao 2020-05-09 20:52:39 -04:00
parent 96330609b7
commit 3ce2173be6
2 changed files with 15 additions and 2 deletions
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15
sys/kern/kern_event.c
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@ -105,6 +105,10 @@ SYSCTL_U64(_kern, OID_AUTO, kq_ws_int_sbt, CTLFLAG_RD, &ws_int_sbt, 0, "KQueue w
/* sysctl for ws_int */ /* sysctl for ws_int */
static uint32_t ws_int = 100; static uint32_t ws_int = 100;
/* sysctl for ws_kn_factor */
static uint32_t ws_kn_factor = 2;
SYSCTL_U32(_kern, OID_AUTO, kq_ws_kn_factor, CTLFLAG_RW, &ws_kn_factor, 0, "KQueue work stealing knote factor.");
static inline void static inline void
update_ws_int_sbt() update_ws_int_sbt()
{ {
@ -2545,6 +2549,7 @@ kevq_dump(struct sbuf *buf, struct kevq *kevq, int level)
"total_fallbacks=\"%ld\" " "total_fallbacks=\"%ld\" "
"total_mismatches=\"%ld\" " "total_mismatches=\"%ld\" "
"total_worksteal=\"%ld\" " "total_worksteal=\"%ld\" "
"total_worksteal_scan=\"%ld\" "
"total_realtime=\"%ld\" " "total_realtime=\"%ld\" "
"total_sched=\"%ld\" " "total_sched=\"%ld\" "
"last_kev=\"%ld\" " "last_kev=\"%ld\" "
@ -2559,6 +2564,7 @@ kevq_dump(struct sbuf *buf, struct kevq *kevq, int level)
kevq->kevq_tot_fallback, kevq->kevq_tot_fallback,
kevq->kevq_tot_kqd_mismatch, kevq->kevq_tot_kqd_mismatch,
kevq->kevq_tot_ws, kevq->kevq_tot_ws,
kevq->kevq_tot_ws_scan,
kevq->kevq_tot_realtime, kevq->kevq_tot_realtime,
kevq->kevq_tot_sched, kevq->kevq_tot_sched,
kevq->kevq_last_kev, kevq->kevq_last_kev,
@ -2861,6 +2867,7 @@ kevq_worksteal(struct kevq *kevq)
//struct knlist *knl; //struct knlist *knl;
struct knote *ws_lst[8]; struct knote *ws_lst[8];
int ws_count; int ws_count;
int scan_count, max_count;
int tgt_count; int tgt_count;
KEVQ_OWNED(kevq); KEVQ_OWNED(kevq);
@ -2869,7 +2876,9 @@ kevq_worksteal(struct kevq *kevq)
kq = kevq->kq; kq = kevq->kq;
ws_count = 0; ws_count = 0;
scan_count = 0;
tgt_count = KQSCHED_GET_FARGS(kq); tgt_count = KQSCHED_GET_FARGS(kq);
max_count = tgt_count * ws_kn_factor;
/* XXX: hack */ /* XXX: hack */
KASSERT(tgt_count <= 8, ("too many kevq ws knotes")); KASSERT(tgt_count <= 8, ("too many kevq ws knotes"));
@ -2897,9 +2906,9 @@ kevq_worksteal(struct kevq *kevq)
KEVQ_OWNED(other_kevq); KEVQ_OWNED(other_kevq);
/* steal from the first because it arrived late */ /* steal from the first because it arrived late */
ws_kn = kevq_peek_knote(other_kevq); ws_kn = kevq_peek_knote(other_kevq);
while((ws_count < tgt_count) && (ws_kn != NULL) && (scan_count < max_count)) {
while((ws_count < tgt_count) && (ws_kn != NULL)) {
/* fast fail */ /* fast fail */
/* holding next_kn here is fine because we are holding the kevq lock during the process */
next_kn = TAILQ_NEXT(ws_kn, kn_tqe); next_kn = TAILQ_NEXT(ws_kn, kn_tqe);
CTR2(KTR_KQ, "ws_kn = %p, next_kn = %p\n", ws_kn, next_kn); CTR2(KTR_KQ, "ws_kn = %p, next_kn = %p\n", ws_kn, next_kn);
@ -2943,6 +2952,7 @@ kevq_worksteal(struct kevq *kevq)
// } // }
end_loop: end_loop:
ws_kn = next_kn; ws_kn = next_kn;
scan_count++;
} }
KEVQ_UNLOCK(other_kevq); KEVQ_UNLOCK(other_kevq);
@ -2951,6 +2961,7 @@ kevq_worksteal(struct kevq *kevq)
KEVQ_LOCK(kevq); KEVQ_LOCK(kevq);
kevq->kevq_state &= ~KEVQ_WS; kevq->kevq_state &= ~KEVQ_WS;
kevq->kevq_tot_ws += ws_count; kevq->kevq_tot_ws += ws_count;
kevq->kevq_tot_ws_scan += scan_count;
for (int i = 0; i < ws_count; i++) { for (int i = 0; i < ws_count; i++) {
knote_enqueue_head(ws_lst[i], kevq); knote_enqueue_head(ws_lst[i], kevq);
knote_leave_flux_ul(ws_lst[i]); knote_leave_flux_ul(ws_lst[i]);

2
sys/sys/eventvar.h
View File

@ -31,6 +31,7 @@
#ifndef _SYS_EVENTVAR_H_ #ifndef _SYS_EVENTVAR_H_
#define _SYS_EVENTVAR_H_ #define _SYS_EVENTVAR_H_
#include <sys/_stdint.h>
#include <sys/queue.h> #include <sys/queue.h>
#ifndef _KERNEL #ifndef _KERNEL
#error "no user-serviceable parts inside" #error "no user-serviceable parts inside"
@ -96,6 +97,7 @@ struct kevq {
uint64_t kevq_tot_realtime; uint64_t kevq_tot_realtime;
uint64_t kevq_tot_syscall; uint64_t kevq_tot_syscall;
uint64_t kevq_tot_ws; uint64_t kevq_tot_ws;
uint64_t kevq_tot_ws_scan;
uint64_t kevq_avg_rlimit; uint64_t kevq_avg_rlimit;
}; };