Date: Sun, 26 Jan 2003 12:45:54 -0800 (PST) From: Matthew Dillon <dillon@apollo.backplane.com> To: Jeff Roberson <jroberson@chesapeake.net> Cc: Julian Elischer <julian@elischer.org>, Steve Kargl <sgk@troutmask.apl.washington.edu>, Robert Watson <rwatson@FreeBSD.ORG>, Gary Jennejohn <garyj@jennejohn.org>, <arch@FreeBSD.ORG> Subject: Re: New scheduler - ULE performance w/ cpu stealing Message-ID: <200301262045.h0QKjsVc067308@apollo.backplane.com> References: <20030126040154.A64928-100000@mail.chesapeake.net>
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I added cpu-stealing code to ULE and it seems to have made a
huge difference. Perhaps you missed something in your local patch
set. Here are the results:
/usr/bin/time make -j 8 buildworld
4BSD - Original scheduler
2414.84 real 2648.92 user 758.28 sys
2399.05 real 2647.84 user 757.78 sys
ULE -
3435.42 real 2500.73 user 581.20 sys
3343.95 real 2501.86 user 581.67 sys
ULE - With cpu stealing code
2489.76 real 2610.33 user 659.74 sys <<<<<<<<<<<<<<<<<<
Next I am going to try removing sched_pickcpu(), but I don't expect
it to improve things (nor do I expect the removal to make things
worse).
-Matt
Index: sched_ule.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/sched_ule.c,v
retrieving revision 1.1
diff -u -r1.1 sched_ule.c
--- sched_ule.c 26 Jan 2003 05:23:15 -0000 1.1
+++ sched_ule.c 26 Jan 2003 20:42:47 -0000
@@ -53,6 +53,9 @@
/* 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 int sched_stealcpu = 1;
+SYSCTL_INT(_kern, OID_AUTO, sched_stealcpu, CTLFLAG_RW, &sched_stealcpu, 0,
+ "Ok to steal KSEs from another cpu (0=disabled, 1=normal)");
static void sched_setup(void *dummy);
SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL)
@@ -554,9 +557,26 @@
cpu = PCPU_GET(cpuid);
kseq = &kseq_cpu[cpu];
- if (runq_check(kseq->ksq_curr) == 0)
- return (runq_check(kseq->ksq_next));
- return (1);
+ if (runq_check(kseq->ksq_curr))
+ return(1);
+ if (runq_check(kseq->ksq_next))
+ return(1);
+
+#ifdef SMP
+ /*
+ * Check other cpus for runnable tasks
+ */
+ if (sched_stealcpu) {
+ for (cpu = 0; cpu < mp_ncpus; ++cpu) {
+ kseq = &kseq_cpu[cpu];
+ if (runq_check(kseq->ksq_curr))
+ return(1);
+ if (runq_check(kseq->ksq_next))
+ return(1);
+ }
+ }
+#endif
+ return (0);
}
void
@@ -573,30 +593,53 @@
}
}
+static __inline
struct kse *
-sched_choose(void)
+sched_choose_kseq(struct kseq *kseq)
{
- struct kseq *kseq;
struct kse *ke;
struct runq *swap;
- int cpu;
- cpu = PCPU_GET(cpuid);
- kseq = &kseq_cpu[cpu];
-
if ((ke = runq_choose(kseq->ksq_curr)) == NULL) {
swap = kseq->ksq_curr;
kseq->ksq_curr = kseq->ksq_next;
kseq->ksq_next = swap;
ke = runq_choose(kseq->ksq_curr);
}
+ return(ke);
+}
+
+struct kse *
+sched_choose(void)
+{
+ struct kseq *kseq;
+ struct kse *ke;
+ int cpu, i;
+
+ cpu = PCPU_GET(cpuid);
+ kseq = &kseq_cpu[cpu];
+
+ ke = sched_choose_kseq(kseq);
if (ke) {
runq_remove(ke->ke_runq, ke);
ke->ke_state = KES_THREAD;
}
-
- return (ke);
+#ifdef SMP
+ else if (sched_stealcpu) {
+ for (i = mp_ncpus - 1; ke == NULL && i; --i) {
+ cpu = (cpu + 1) % mp_ncpus;
+ kseq = &kseq_cpu[cpu];
+ ke = sched_choose_kseq(kseq);
+ }
+ if (ke) {
+ runq_remove(ke->ke_runq, ke);
+ ke->ke_state = KES_THREAD;
+ }
+ }
+#endif
+ return(ke);
}
+
void
sched_add(struct kse *ke)
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