Mailing List Archive

# HG changeset patch
# User Keir Fraser <keir@xen.org>
# Date 1293179415 0
# Node ID cf1ea603b340f6b56afd0b4036d5dd99e947fcf5
# Parent 00fc33d9f6918c8f5170e4b7067e2460afa235ac
credit2: Track average load contributed by a vcpu

Track the amount of load contributed by a particular vcpu, to help
us make informed decisions about what will happen if we make a move.

Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com>
---
xen/common/sched_credit2.c | 91 ++++++++++++++++++++++++++++++++++++++-------
1 files changed, 77 insertions(+), 14 deletions(-)

diff -r 00fc33d9f691 -r cf1ea603b340 xen/common/sched_credit2.c
--- a/xen/common/sched_credit2.c Fri Dec 24 08:29:53 2010 +0000
+++ b/xen/common/sched_credit2.c Fri Dec 24 08:30:15 2010 +0000
@@ -45,6 +45,8 @@
#define TRC_CSCHED2_SCHED_TASKLET TRC_SCHED_CLASS + 8
#define TRC_CSCHED2_UPDATE_LOAD TRC_SCHED_CLASS + 9
#define TRC_CSCHED2_RUNQ_ASSIGN TRC_SCHED_CLASS + 10
+#define TRC_CSCHED2_UPDATE_VCPU_LOAD TRC_SCHED_CLASS + 11
+#define TRC_CSCHED2_UPDATE_RUNQ_LOAD TRC_SCHED_CLASS + 12

/*
* WARNING: This is still in an experimental phase. Status and work can be found at the
@@ -241,6 +243,9 @@ struct csched_vcpu {
s_time_t start_time; /* When we were scheduled (used for credit) */
unsigned flags; /* 16 bits doesn't seem to play well with clear_bit() */

+ /* Individual contribution to load */
+ s_time_t load_last_update; /* Last time average was updated */
+ s_time_t avgload; /* Decaying queue load */
};

/*
@@ -286,8 +291,8 @@ __runq_elem(struct list_head *elem)
}

static void
-update_load(const struct scheduler *ops,
- struct csched_runqueue_data *rqd, int change, s_time_t now)
+__update_runq_load(const struct scheduler *ops,
+ struct csched_runqueue_data *rqd, int change, s_time_t now)
{
struct csched_private *prv = CSCHED_PRIV(ops);
s_time_t delta=-1;
@@ -296,7 +301,7 @@ update_load(const struct scheduler *ops,

if ( rqd->load_last_update + (1ULL<<prv->load_window_shift) < now )
{
- rqd->avgload = rqd->load << (1ULL<prv->load_window_shift);
+ rqd->avgload = (unsigned long long)rqd->load << prv->load_window_shift;
}
else
{
@@ -306,21 +311,76 @@ update_load(const struct scheduler *ops,
( ( delta * ( (unsigned long long)rqd->load << prv->load_window_shift ) )
+ ( ((1ULL<<prv->load_window_shift) - delta) * rqd->avgload ) ) >> prv->load_window_shift;
}
-
rqd->load += change;
rqd->load_last_update = now;
+
{
struct {
- unsigned load:4, avgload:28;
- int delta;
+ unsigned rq_load:4, rq_avgload:28;
+ unsigned rq_id:4;
} d;
- d.load = rqd->load;
- d.avgload = rqd->avgload;
- d.delta = delta;
- trace_var(TRC_CSCHED2_UPDATE_LOAD, 0,
+ d.rq_id=rqd->id;
+ d.rq_load = rqd->load;
+ d.rq_avgload = rqd->avgload;
+ trace_var(TRC_CSCHED2_UPDATE_RUNQ_LOAD, 1,
sizeof(d),
(unsigned char *)&d);
}
+}
+
+static void
+__update_svc_load(const struct scheduler *ops,
+ struct csched_vcpu *svc, int change, s_time_t now)
+{
+ struct csched_private *prv = CSCHED_PRIV(ops);
+ s_time_t delta=-1;
+ int vcpu_load;
+
+ if ( change == -1 )
+ vcpu_load = 1;
+ else if ( change == 1 )
+ vcpu_load = 0;
+ else
+ vcpu_load = vcpu_runnable(svc->vcpu);
+
+ now >>= LOADAVG_GRANULARITY_SHIFT;
+
+ if ( svc->load_last_update + (1ULL<<prv->load_window_shift) < now )
+ {
+ svc->avgload = (unsigned long long)vcpu_load << prv->load_window_shift;
+ }
+ else
+ {
+ delta = now - svc->load_last_update;
+
+ svc->avgload =
+ ( ( delta * ( (unsigned long long)vcpu_load << prv->load_window_shift ) )
+ + ( ((1ULL<<prv->load_window_shift) - delta) * svc->avgload ) ) >> prv->load_window_shift;
+ }
+ svc->load_last_update = now;
+
+ {
+ struct {
+ unsigned dom:16,vcpu:16;
+ unsigned v_avgload:32;
+ } d;
+ d.dom = svc->vcpu->domain->domain_id;
+ d.vcpu = svc->vcpu->vcpu_id;
+ d.v_avgload = svc->avgload;
+ trace_var(TRC_CSCHED2_UPDATE_VCPU_LOAD, 1,
+ sizeof(d),
+ (unsigned char *)&d);
+ }
+}
+
+static void
+update_load(const struct scheduler *ops,
+ struct csched_runqueue_data *rqd,
+ struct csched_vcpu *svc, int change, s_time_t now)
+{
+ __update_runq_load(ops, rqd, change, now);
+ if ( svc )
+ __update_svc_load(ops, svc, change, now);
}

static int
@@ -672,6 +732,9 @@ csched_alloc_vdata(const struct schedule

svc->credit = CSCHED_CREDIT_INIT;
svc->weight = svc->sdom->weight;
+ /* Starting load of 50% */
+ svc->avgload = 1ULL << (CSCHED_PRIV(ops)->load_window_shift - 1);
+ svc->load_last_update = NOW();
}
else
{
@@ -817,7 +880,7 @@ csched_vcpu_sleep(const struct scheduler
else if ( __vcpu_on_runq(svc) )
{
BUG_ON(svc->rqd != RQD(ops, vc->processor));
- update_load(ops, svc->rqd, -1, NOW());
+ update_load(ops, svc->rqd, svc, -1, NOW());
__runq_remove(svc);
}
else if ( test_bit(__CSFLAG_delayed_runq_add, &svc->flags) )
@@ -866,7 +929,7 @@ csched_vcpu_wake(const struct scheduler

now = NOW();

- update_load(ops, svc->rqd, 1, now);
+ update_load(ops, svc->rqd, svc, 1, now);

/* Put the VCPU on the runq */
runq_insert(ops, vc->processor, svc);
@@ -907,7 +970,7 @@ csched_context_saved(const struct schedu
runq_tickle(ops, vc->processor, svc, now);
}
else if ( !is_idle_vcpu(vc) )
- update_load(ops, svc->rqd, -1, now);
+ update_load(ops, svc->rqd, svc, -1, now);

vcpu_schedule_unlock_irq(vc);
}
@@ -1339,7 +1402,7 @@ csched_schedule(
cpu_set(cpu, rqd->idle);
/* Make sure avgload gets updated periodically even
* if there's no activity */
- update_load(ops, rqd, 0, now);
+ update_load(ops, rqd, NULL, 0, now);
}

/*

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