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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v2 06/10] xen: tracing: add trace records for schedule and rate-limiting.
As far as {csched, csched2, rt}_schedule() are concerned,
an "empty" event, would already make it easier to read and
understand a trace.
But while there, add a few useful information, like
if the cpu that is going through the scheduler has
been tickled or not, if it is currently idle, etc
(they vary, on a per-scheduler basis).
For Credit1 and Credit2, add a record about when
rate-limiting kicks in too.
Signed-off-by: Dario Faggioli <dario.faggioli@xxxxxxxxxx>
---
Cc: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
Cc: Meng Xu <mengxu@xxxxxxxxxxxxx>
Cc: Anshul Makkar <anshul.makkar@xxxxxxxxxx>
---
Changes from v1:
* corrected the schedule record for sched_rt.c, as pointed out during review;
* pack the Credit1 records as well, as requested during review.
---
xen/common/sched_credit.c | 32 ++++++++++++++++++++++++++++++++
xen/common/sched_credit2.c | 40 +++++++++++++++++++++++++++++++++++++++-
xen/common/sched_rt.c | 15 +++++++++++++++
3 files changed, 86 insertions(+), 1 deletion(-)
diff --git a/xen/common/sched_credit.c b/xen/common/sched_credit.c
index 5700763..fc3a321 100644
--- a/xen/common/sched_credit.c
+++ b/xen/common/sched_credit.c
@@ -133,6 +133,8 @@
#define TRC_CSCHED_TICKLE TRC_SCHED_CLASS_EVT(CSCHED, 6)
#define TRC_CSCHED_BOOST_START TRC_SCHED_CLASS_EVT(CSCHED, 7)
#define TRC_CSCHED_BOOST_END TRC_SCHED_CLASS_EVT(CSCHED, 8)
+#define TRC_CSCHED_SCHEDULE TRC_SCHED_CLASS_EVT(CSCHED, 9)
+#define TRC_CSCHED_RATELIMIT TRC_SCHED_CLASS_EVT(CSCHED, 10)
/*
@@ -1774,6 +1776,23 @@ csched_schedule(
SCHED_STAT_CRANK(schedule);
CSCHED_VCPU_CHECK(current);
+ /*
+ * Here in Credit1 code, we usually just call TRACE_nD() helpers, and
+ * don't care about packing. But scheduling happens very often, so it
+ * actually is important that the record is as small as possible.
+ */
+ if ( unlikely(tb_init_done) )
+ {
+ struct {
+ unsigned cpu:16, tasklet:8, idle:8;
+ } d;
+ d.cpu = cpu;
+ d.tasklet = tasklet_work_scheduled;
+ d.idle = is_idle_vcpu(current);
+ __trace_var(TRC_CSCHED_SCHEDULE, 1, sizeof(d),
+ (unsigned char *)&d);
+ }
+
runtime = now - current->runstate.state_entry_time;
if ( runtime < 0 ) /* Does this ever happen? */
runtime = 0;
@@ -1829,6 +1848,19 @@ csched_schedule(
tslice = MICROSECS(prv->ratelimit_us) - runtime;
if ( unlikely(runtime < CSCHED_MIN_TIMER) )
tslice = CSCHED_MIN_TIMER;
+ if ( unlikely(tb_init_done) )
+ {
+ struct {
+ unsigned vcpu:16, dom:16;
+ unsigned runtime;
+ } d;
+ d.dom = scurr->vcpu->domain->domain_id;
+ d.vcpu = scurr->vcpu->vcpu_id;
+ d.runtime = runtime;
+ __trace_var(TRC_CSCHED_RATELIMIT, 1, sizeof(d),
+ (unsigned char *)&d);
+ }
+
ret.migrated = 0;
goto out;
}
diff --git a/xen/common/sched_credit2.c b/xen/common/sched_credit2.c
index fde61ef..5cf3f16 100644
--- a/xen/common/sched_credit2.c
+++ b/xen/common/sched_credit2.c
@@ -55,6 +55,8 @@
#define TRC_CSCHED2_LOAD_BALANCE TRC_SCHED_CLASS_EVT(CSCHED2, 17)
#define TRC_CSCHED2_PICKED_CPU TRC_SCHED_CLASS_EVT(CSCHED2, 19)
#define TRC_CSCHED2_RUNQ_CANDIDATE TRC_SCHED_CLASS_EVT(CSCHED2, 20)
+#define TRC_CSCHED2_SCHEDULE TRC_SCHED_CLASS_EVT(CSCHED2, 21)
+#define TRC_CSCHED2_RATELIMIT TRC_SCHED_CLASS_EVT(CSCHED2, 22)
/*
* WARNING: This is still in an experimental phase. Status and work can be
found at the
@@ -2288,12 +2290,29 @@ runq_candidate(struct csched2_runqueue_data *rqd,
* no point forcing it to do so until rate limiting expires.
*/
if ( __test_and_clear_bit(__CSFLAG_vcpu_yield, &scurr->flags) )
+ {
yield_bias = CSCHED2_YIELD_BIAS;
+ }
else if ( prv->ratelimit_us && !is_idle_vcpu(scurr->vcpu) &&
vcpu_runnable(scurr->vcpu) &&
(now - scurr->vcpu->runstate.state_entry_time) <
MICROSECS(prv->ratelimit_us) )
+ {
+ if ( unlikely(tb_init_done) )
+ {
+ struct {
+ unsigned vcpu:16, dom:16;
+ unsigned runtime;
+ } d;
+ d.dom = scurr->vcpu->domain->domain_id;
+ d.vcpu = scurr->vcpu->vcpu_id;
+ d.runtime = now - scurr->vcpu->runstate.state_entry_time;
+ __trace_var(TRC_CSCHED2_RATELIMIT, 1,
+ sizeof(d),
+ (unsigned char *)&d);
+ }
return scurr;
+ }
/* Default to current if runnable, idle otherwise */
if ( vcpu_runnable(scurr->vcpu) )
@@ -2383,6 +2402,7 @@ csched2_schedule(
struct csched2_vcpu *snext = NULL;
unsigned int skipped_vcpus = 0;
struct task_slice ret;
+ bool_t tickled;
SCHED_STAT_CRANK(schedule);
CSCHED2_VCPU_CHECK(current);
@@ -2397,13 +2417,31 @@ csched2_schedule(
BUG_ON(!is_idle_vcpu(scurr->vcpu) && scurr->rqd != rqd);
/* Clear "tickled" bit now that we've been scheduled */
- if ( cpumask_test_cpu(cpu, &rqd->tickled) )
+ tickled = cpumask_test_cpu(cpu, &rqd->tickled);
+ if ( tickled )
{
__cpumask_clear_cpu(cpu, &rqd->tickled);
cpumask_andnot(cpumask_scratch, &rqd->idle, &rqd->tickled);
smt_idle_mask_set(cpu, cpumask_scratch, &rqd->smt_idle);
}
+ if ( unlikely(tb_init_done) )
+ {
+ struct {
+ unsigned cpu:16, rq_id:16;
+ unsigned tasklet:8, idle:8, smt_idle:8, tickled:8;
+ } d;
+ d.cpu = cpu;
+ d.rq_id = c2r(ops, cpu);
+ d.tasklet = tasklet_work_scheduled;
+ d.idle = is_idle_vcpu(current);
+ d.smt_idle = cpumask_test_cpu(cpu, &rqd->smt_idle);
+ d.tickled = tickled;
+ __trace_var(TRC_CSCHED2_SCHEDULE, 1,
+ sizeof(d),
+ (unsigned char *)&d);
+ }
+
/* Update credits */
burn_credits(rqd, scurr, now);
diff --git a/xen/common/sched_rt.c b/xen/common/sched_rt.c
index 41c61a7..d95f798 100644
--- a/xen/common/sched_rt.c
+++ b/xen/common/sched_rt.c
@@ -160,6 +160,7 @@
#define TRC_RTDS_BUDGET_BURN TRC_SCHED_CLASS_EVT(RTDS, 3)
#define TRC_RTDS_BUDGET_REPLENISH TRC_SCHED_CLASS_EVT(RTDS, 4)
#define TRC_RTDS_SCHED_TASKLET TRC_SCHED_CLASS_EVT(RTDS, 5)
+#define TRC_RTDS_SCHEDULE TRC_SCHED_CLASS_EVT(RTDS, 6)
static void repl_timer_handler(void *data);
@@ -1035,6 +1036,20 @@ rt_schedule(const struct scheduler *ops, s_time_t now,
bool_t tasklet_work_sched
struct rt_vcpu *snext = NULL;
struct task_slice ret = { .migrated = 0 };
+ /* TRACE */
+ {
+ struct __packed {
+ unsigned cpu:16, tasklet:8, tickled:4, idle:4;
+ } d;
+ d.cpu = cpu;
+ d.tasklet = tasklet_work_scheduled;
+ d.tickled = cpumask_test_cpu(cpu, &prv->tickled);
+ d.idle = is_idle_vcpu(current);
+ trace_var(TRC_RTDS_SCHEDULE, 1,
+ sizeof(d),
+ (unsigned char *)&d);
+ }
+
/* clear ticked bit now that we've been scheduled */
cpumask_clear_cpu(cpu, &prv->tickled);
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