Mailing List Archive

# HG changeset patch
# User Keir Fraser <keir@xen.org>
# Date 1293179484 0
# Node ID 41d1affef5969003eb3cb5f6313421c12db4d0c2
# Parent df310dcd19cb7b5840a1f73431abb7aa87531122
credit2: Use loadavg to pick cpus, instead of instantaneous load

Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com>
---
xen/common/sched_credit2.c | 33 +++++++++++++++++++++++----------
1 files changed, 23 insertions(+), 10 deletions(-)

diff -r df310dcd19cb -r 41d1affef596 xen/common/sched_credit2.c
--- a/xen/common/sched_credit2.c Fri Dec 24 08:31:04 2010 +0000
+++ b/xen/common/sched_credit2.c Fri Dec 24 08:31:24 2010 +0000
@@ -996,13 +996,14 @@ csched_context_saved(const struct schedu
vcpu_schedule_unlock_irq(vc);
}

-#define MAX_LOAD (1<<30);
+#define MAX_LOAD (1ULL<<60);
static int
choose_cpu(const struct scheduler *ops, struct vcpu *vc)
{
struct csched_private *prv = CSCHED_PRIV(ops);
- int i, min_load, min_rqi = -1, new_cpu;
+ int i, min_rqi = -1, new_cpu;
struct csched_vcpu *svc = CSCHED_VCPU(vc);
+ s_time_t min_avgload;

BUG_ON(cpus_empty(prv->active_queues));

@@ -1053,27 +1054,39 @@ choose_cpu(const struct scheduler *ops,

/* FIXME: Pay attention to cpu affinity */

- min_load = MAX_LOAD;
+ min_avgload = MAX_LOAD;

/* Find the runqueue with the lowest instantaneous load */
for_each_cpu_mask(i, prv->active_queues)
{
struct csched_runqueue_data *rqd;
+ s_time_t rqd_avgload;

rqd = prv->rqd + i;

/* If checking a different runqueue, grab the lock,
- * read the avg, and then release the lock. */
- if ( rqd != svc->rqd
- && ! spin_trylock(&rqd->lock) )
+ * read the avg, and then release the lock.
+ *
+ * If on our own runqueue, don't grab or release the lock;
+ * but subtract our own load from the runqueue load to simulate
+ * impartiality */
+ if ( rqd == svc->rqd )
+ {
+ rqd_avgload = rqd->b_avgload - svc->avgload;
+ }
+ else if ( spin_trylock(&rqd->lock) )
+ {
+ rqd_avgload = rqd->b_avgload;
+ spin_unlock(&rqd->lock);
+ }
+ else
continue;
- if ( prv->rqd[i].load < min_load )
+
+ if ( rqd_avgload < min_avgload )
{
- min_load=prv->rqd[i].load;
+ min_avgload = rqd_avgload;
min_rqi=i;
}
- if ( rqd != svc->rqd )
- spin_unlock(&rqd->lock);
}

/* We didn't find anyone (most likely because of spinlock contention); leave it where it is */

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