# HG changeset patch
# User Emmanuel Ackaouy <ack@xxxxxxxxxxxxx>
# Node ID b21246720fde43b11835d814e9755f1f3888f9e4
# Parent d6802cfaf5f8abb7bec33e65425f41d2086d4b04
[XEN] Cleanup and improve accuracy of credit scheduler accounting code
Signed-off-by: Emmanuel Ackaouy <ack@xxxxxxxxxxxxx>
---
xen/common/sched_credit.c | 60 +++++++++++++++++++++++++++-------------------
1 files changed, 36 insertions(+), 24 deletions(-)
diff -r d6802cfaf5f8 -r b21246720fde xen/common/sched_credit.c
--- a/xen/common/sched_credit.c Mon Oct 30 14:28:29 2006 +0000
+++ b/xen/common/sched_credit.c Mon Oct 30 17:35:11 2006 +0000
@@ -36,11 +36,17 @@
/*
* Basic constants
*/
-#define CSCHED_TICK 10 /* milliseconds */
-#define CSCHED_TSLICE 30 /* milliseconds */
-#define CSCHED_ACCT_NTICKS 3
-#define CSCHED_ACCT_PERIOD (CSCHED_ACCT_NTICKS * CSCHED_TICK)
-#define CSCHED_DEFAULT_WEIGHT 256
+#define CSCHED_DEFAULT_WEIGHT 256
+#define CSCHED_TICKS_PER_TSLICE 3
+#define CSCHED_TICKS_PER_ACCT 3
+#define CSCHED_MSECS_PER_TICK 10
+#define CSCHED_MSECS_PER_TSLICE \
+ (CSCHED_MSECS_PER_TICK * CSCHED_TICKS_PER_TSLICE)
+#define CSCHED_CREDITS_PER_TICK 100
+#define CSCHED_CREDITS_PER_TSLICE \
+ (CSCHED_CREDITS_PER_TICK * CSCHED_TICKS_PER_TSLICE)
+#define CSCHED_CREDITS_PER_ACCT \
+ (CSCHED_CREDITS_PER_TICK * CSCHED_TICKS_PER_ACCT)
/*
@@ -314,7 +320,7 @@ csched_pcpu_init(int cpu)
spin_lock_irqsave(&csched_priv.lock, flags);
/* Initialize/update system-wide config */
- csched_priv.credit += CSCHED_ACCT_PERIOD;
+ csched_priv.credit += CSCHED_CREDITS_PER_ACCT;
if ( csched_priv.ncpus <= cpu )
csched_priv.ncpus = cpu + 1;
if ( csched_priv.master >= csched_priv.ncpus )
@@ -439,8 +445,6 @@ __csched_vcpu_acct_idle_locked(struct cs
list_del_init(&sdom->active_sdom_elem);
csched_priv.weight -= sdom->weight;
}
-
- atomic_set(&svc->credit, 0);
}
static int
@@ -767,7 +771,7 @@ csched_acct(void)
* for one full accounting period. We allow a domain to earn more
* only when the system-wide credit balance is negative.
*/
- credit_peak = sdom->active_vcpu_count * CSCHED_ACCT_PERIOD;
+ credit_peak = sdom->active_vcpu_count * CSCHED_CREDITS_PER_ACCT;
if ( csched_priv.credit_balance < 0 )
{
credit_peak += ( ( -csched_priv.credit_balance * sdom->weight) +
@@ -776,7 +780,9 @@ csched_acct(void)
}
if ( sdom->cap != 0U )
{
- uint32_t credit_cap = ((sdom->cap * CSCHED_ACCT_PERIOD) + 99) /
100;
+ uint32_t credit_cap;
+
+ credit_cap = ((sdom->cap * CSCHED_CREDITS_PER_ACCT) + 99) / 100;
if ( credit_cap < credit_peak )
credit_peak = credit_cap;
}
@@ -839,10 +845,10 @@ csched_acct(void)
else
svc->pri = CSCHED_PRI_TS_PARKED;
- if ( credit < -CSCHED_TSLICE )
+ if ( credit < -CSCHED_CREDITS_PER_TSLICE )
{
CSCHED_STAT_CRANK(acct_min_credit);
- credit = -CSCHED_TSLICE;
+ credit = -CSCHED_CREDITS_PER_TSLICE;
atomic_set(&svc->credit, credit);
}
}
@@ -850,8 +856,12 @@ csched_acct(void)
{
svc->pri = CSCHED_PRI_TS_UNDER;
- if ( credit > CSCHED_TSLICE )
+ if ( credit > CSCHED_CREDITS_PER_TSLICE )
+ {
__csched_vcpu_acct_idle_locked(svc);
+ credit = 0;
+ atomic_set(&svc->credit, credit);
+ }
}
svc->credit_last = credit;
@@ -881,7 +891,7 @@ csched_tick(unsigned int cpu)
*/
if ( likely(sdom != NULL) )
{
- csched_vcpu_acct(svc, CSCHED_TICK);
+ csched_vcpu_acct(svc, CSCHED_CREDITS_PER_TICK);
}
/*
@@ -891,7 +901,7 @@ csched_tick(unsigned int cpu)
* we could distribute or at the very least cycle the duty.
*/
if ( (csched_priv.master == cpu) &&
- (per_cpu(schedule_data, cpu).tick % CSCHED_ACCT_NTICKS) == 0 )
+ (per_cpu(schedule_data, cpu).tick % CSCHED_TICKS_PER_ACCT) == 0 )
{
csched_acct();
}
@@ -1069,7 +1079,7 @@ csched_schedule(s_time_t now)
/*
* Return task to run next...
*/
- ret.time = MILLISECS(CSCHED_TSLICE);
+ ret.time = MILLISECS(CSCHED_MSECS_PER_TSLICE);
ret.task = snext->vcpu;
CSCHED_VCPU_CHECK(ret.task);
@@ -1150,20 +1160,22 @@ csched_dump(void)
"\tcredit balance = %d\n"
"\tweight = %u\n"
"\trunq_sort = %u\n"
- "\ttick = %dms\n"
- "\ttslice = %dms\n"
- "\taccounting period = %dms\n"
- "\tdefault-weight = %d\n",
+ "\tdefault-weight = %d\n"
+ "\tmsecs per tick = %dms\n"
+ "\tcredits per tick = %d\n"
+ "\tticks per tslice = %d\n"
+ "\tticks per acct = %d\n",
csched_priv.ncpus,
csched_priv.master,
csched_priv.credit,
csched_priv.credit_balance,
csched_priv.weight,
csched_priv.runq_sort,
- CSCHED_TICK,
- CSCHED_TSLICE,
- CSCHED_ACCT_PERIOD,
- CSCHED_DEFAULT_WEIGHT);
+ CSCHED_DEFAULT_WEIGHT,
+ CSCHED_MSECS_PER_TICK,
+ CSCHED_CREDITS_PER_TICK,
+ CSCHED_TICKS_PER_TSLICE,
+ CSCHED_TICKS_PER_ACCT);
printk("idlers: 0x%lx\n", csched_priv.idlers.bits[0]);
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