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authorPeter Zijlstra <peterz@infradead.org>2017-11-13 14:28:30 +0100
committerIngo Molnar <mingo@kernel.org>2018-03-12 15:28:49 +0100
commit1cac7b1ae3579457200213303fc28ca13b75592f (patch)
tree2db8f225af531e240eacfe20494cc89a70e8c47f
parent161c85fab7875f306eee9655dee71068feeb14ce (diff)
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>
-rw-r--r--kernel/events/core.c157
1 files changed, 108 insertions, 49 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 22165b009d73..2d8c0208ca4a 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1609,6 +1609,21 @@ perf_event_groups_first(struct perf_event_groups *groups, int cpu)
}
/*
+ * 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.
*
* Re-insert the leftmost event at the tail of the 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 void
-ctx_pinned_sched_in(struct perf_event_context *ctx,
- struct perf_cpu_context *cpuctx)
+static int visit_groups_merge(struct perf_event_groups *groups, int cpu,
+ int (*func)(struct perf_event *, void *), void *data)
{
- int sw = -1, cpu = smp_processor_id();
- struct perf_event *event;
- int can_add_hw;
+ struct perf_event **evt, *evt1, *evt2;
+ int ret;
- 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);
+ 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);
}
- 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);
- }
+ 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_flexible_sched_in(struct perf_event_context *ctx,
- struct perf_cpu_context *cpuctx)
+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 = 1;
+ struct sched_in_data sid = {
+ .ctx = ctx,
+ .cpuctx = cpuctx,
+ .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);
+ visit_groups_merge(&ctx->pinned_groups,
+ smp_processor_id(),
+ pinned_sched_in, &sid);
+}
- 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);
+static void
+ctx_flexible_sched_in(struct perf_event_context *ctx,
+ struct perf_cpu_context *cpuctx)
+{
+ 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