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perf/core: Fix event schedule order 

Scheduling in events with cpu=-1 before events with cpu=# changes
semantics and is undesirable in that it would priorize these events.

Given that groups->index is across all groups we actually have an
inter-group ordering, meaning we can merge-sort two groups, which is
just what we need to preserve semantics.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Carrillo-Cisneros <davidcc@google.com>
Cc: Dmitri Prokhorov <Dmitry.Prohorov@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Valery Cherepennikov <valery.cherepennikov@intel.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2017-11-13 14:28:30 +01:00 committed by Ingo Molnar
parent 161c85fab7
commit 1cac7b1ae3
1 changed files with 109 additions and 50 deletions
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159
kernel/events/core.c
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@ -1608,6 +1608,21 @@ perf_event_groups_first(struct perf_event_groups *groups, int cpu)
return match;
}
/*
* Like rb_entry_next_safe() for the @cpu subtree.
*/
static struct perf_event *
perf_event_groups_next(struct perf_event *event)
{
struct perf_event *next;
next = rb_entry_safe(rb_next(&event->group_node), typeof(*event), group_node);
if (next && next->cpu == event->cpu)
return next;
return NULL;
}
/*
* Rotate the @cpu subtree.
*
@ -2354,22 +2369,6 @@ static int group_can_go_on(struct perf_event *event,
return can_add_hw;
}
static int
flexible_group_sched_in(struct perf_event *event,
struct perf_event_context *ctx,
struct perf_cpu_context *cpuctx,
int *can_add_hw)
{
if (event->state <= PERF_EVENT_STATE_OFF || !event_filter_match(event))
return 0;
if (group_can_go_on(event, cpuctx, *can_add_hw))
if (group_sched_in(event, cpuctx, ctx))
*can_add_hw = 0;
return 1;
}
static void add_event_to_ctx(struct perf_event *event,
struct perf_event_context *ctx)
{
@ -3185,52 +3184,112 @@ static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
}
static int visit_groups_merge(struct perf_event_groups *groups, int cpu,
int (*func)(struct perf_event *, void *), void *data)
{
struct perf_event **evt, *evt1, *evt2;
int ret;
evt1 = perf_event_groups_first(groups, -1);
evt2 = perf_event_groups_first(groups, cpu);
while (evt1 || evt2) {
if (evt1 && evt2) {
if (evt1->group_index < evt2->group_index)
evt = &evt1;
else
evt = &evt2;
} else if (evt1) {
evt = &evt1;
} else {
evt = &evt2;
}
ret = func(*evt, data);
if (ret)
return ret;
*evt = perf_event_groups_next(*evt);
}
return 0;
}
struct sched_in_data {
struct perf_event_context *ctx;
struct perf_cpu_context *cpuctx;
int can_add_hw;
};
static int pinned_sched_in(struct perf_event *event, void *data)
{
struct sched_in_data *sid = data;
if (event->state <= PERF_EVENT_STATE_OFF)
return 0;
if (!event_filter_match(event))
return 0;
if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw))
group_sched_in(event, sid->cpuctx, sid->ctx);
/*
* If this pinned group hasn't been scheduled,
* put it in error state.
*/
if (event->state == PERF_EVENT_STATE_INACTIVE)
perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
return 0;
}
static int flexible_sched_in(struct perf_event *event, void *data)
{
struct sched_in_data *sid = data;
if (event->state <= PERF_EVENT_STATE_OFF)
return 0;
if (!event_filter_match(event))
return 0;
if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
if (group_sched_in(event, sid->cpuctx, sid->ctx))
sid->can_add_hw = 0;
}
return 0;
}
static void
ctx_pinned_sched_in(struct perf_event_context *ctx,
struct perf_cpu_context *cpuctx)
{
int sw = -1, cpu = smp_processor_id();
struct perf_event *event;
int can_add_hw;
struct sched_in_data sid = {
.ctx = ctx,
.cpuctx = cpuctx,
.can_add_hw = 1,
};
perf_event_groups_for_each_cpu(event, sw,
&ctx->pinned_groups, group_node) {
can_add_hw = 1;
if (flexible_group_sched_in(event, ctx, cpuctx, &can_add_hw)) {
if (event->state == PERF_EVENT_STATE_INACTIVE)
perf_event_set_state(event,
PERF_EVENT_STATE_ERROR);
}
}
perf_event_groups_for_each_cpu(event, cpu,
&ctx->pinned_groups, group_node) {
can_add_hw = 1;
if (flexible_group_sched_in(event, ctx, cpuctx, &can_add_hw)) {
if (event->state == PERF_EVENT_STATE_INACTIVE)
perf_event_set_state(event,
PERF_EVENT_STATE_ERROR);
}
}
visit_groups_merge(&ctx->pinned_groups,
smp_processor_id(),
pinned_sched_in, &sid);
}
static void
ctx_flexible_sched_in(struct perf_event_context *ctx,
struct perf_cpu_context *cpuctx)
{
int sw = -1, cpu = smp_processor_id();
struct perf_event *event;
int can_add_hw = 1;
perf_event_groups_for_each_cpu(event, sw,
&ctx->flexible_groups, group_node)
flexible_group_sched_in(event, ctx, cpuctx, &can_add_hw);
can_add_hw = 1;
perf_event_groups_for_each_cpu(event, cpu,
&ctx->flexible_groups, group_node)
flexible_group_sched_in(event, ctx, cpuctx, &can_add_hw);
struct sched_in_data sid = {
.ctx = ctx,
.cpuctx = cpuctx,
.can_add_hw = 1,
};
visit_groups_merge(&ctx->flexible_groups,
smp_processor_id(),
flexible_sched_in, &sid);
}
static void