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perf/x86/uncore: Fix event group support

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[ Upstream commit 75be6f703a ]

The events in the same group don't start or stop simultaneously.
Here is the ftrace when enabling event group for uncore_iio_0:

  # perf stat -e "{uncore_iio_0/event=0x1/,uncore_iio_0/event=0xe/}"

            <idle>-0     [000] d.h.  8959.064832: read_msr: a41, value
  b2b0b030		//Read counter reg of IIO unit0 counter0
            <idle>-0     [000] d.h.  8959.064835: write_msr: a48, value
  400001			//Write Ctrl reg of IIO unit0 counter0 to enable
  counter0. <------ Although counter0 is enabled, Unit Ctrl is still
  freezed. Nothing will count. We are still good here.
            <idle>-0     [000] d.h.  8959.064836: read_msr: a40, value
  30100                   //Read Unit Ctrl reg of IIO unit0
            <idle>-0     [000] d.h.  8959.064838: write_msr: a40, value
  30000			//Write Unit Ctrl reg of IIO unit0 to enable all
  counters in the unit by clear Freeze bit  <------Unit0 is un-freezed.
  Counter0 has been enabled. Now it starts counting. But counter1 has not
  been enabled yet. The issue starts here.
            <idle>-0     [000] d.h.  8959.064846: read_msr: a42, value 0
			//Read counter reg of IIO unit0 counter1
            <idle>-0     [000] d.h.  8959.064847: write_msr: a49, value
  40000e			//Write Ctrl reg of IIO unit0 counter1 to enable
  counter1.   <------ Now, counter1 just starts to count. Counter0 has
  been running for a while.

Current code un-freezes the Unit Ctrl right after the first counter is
enabled. The subsequent group events always loses some counter values.

Implement pmu_enable and pmu_disable support for uncore, which can help
to batch hardware accesses.

No one uses uncore_enable_box and uncore_disable_box. Remove them.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-drivers-review@eclists.intel.com
Cc: linux-perf@eclists.intel.com
Fixes: 087bfbb032 ("perf/x86: Add generic Intel uncore PMU support")
Link: https://lkml.kernel.org/r/1572014593-31591-1-git-send-email-kan.liang@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Kan Liang 2019-10-25 07:43:13 -07:00 • committed by Greg Kroah-Hartman
commit ef38f4d123
2 changed files with 38 additions and 18 deletions
Download patch file Download diff file Expand all files Collapse all files

44
arch/x86/events/intel/uncore.c
View file

@ -485,10 +485,8 @@ void uncore_pmu_event_start(struct perf_event *event, int flags)
local64_set(&event->hw.prev_count, uncore_read_counter(box, event));
uncore_enable_event(box, event);
if (box->n_active == 1) {
uncore_enable_box(box);
if (box->n_active == 1)
uncore_pmu_start_hrtimer(box);
}
}
void uncore_pmu_event_stop(struct perf_event *event, int flags)
@ -512,10 +510,8 @@ void uncore_pmu_event_stop(struct perf_event *event, int flags)
WARN_ON_ONCE(hwc->state & PERF_HES_STOPPED);
hwc->state |= PERF_HES_STOPPED;
if (box->n_active == 0) {
uncore_disable_box(box);
if (box->n_active == 0)
uncore_pmu_cancel_hrtimer(box);
}
}
if ((flags & PERF_EF_UPDATE) && !(hwc->state & PERF_HES_UPTODATE)) {
@ -769,6 +765,40 @@ static int uncore_pmu_event_init(struct perf_event *event)
return ret;
}
static void uncore_pmu_enable(struct pmu *pmu)
{
struct intel_uncore_pmu *uncore_pmu;
struct intel_uncore_box *box;
uncore_pmu = container_of(pmu, struct intel_uncore_pmu, pmu);
if (!uncore_pmu)
return;
box = uncore_pmu_to_box(uncore_pmu, smp_processor_id());
if (!box)
return;
if (uncore_pmu->type->ops->enable_box)
uncore_pmu->type->ops->enable_box(box);
}
static void uncore_pmu_disable(struct pmu *pmu)
{
struct intel_uncore_pmu *uncore_pmu;
struct intel_uncore_box *box;
uncore_pmu = container_of(pmu, struct intel_uncore_pmu, pmu);
if (!uncore_pmu)
return;
box = uncore_pmu_to_box(uncore_pmu, smp_processor_id());
if (!box)
return;
if (uncore_pmu->type->ops->disable_box)
uncore_pmu->type->ops->disable_box(box);
}
static ssize_t uncore_get_attr_cpumask(struct device *dev,
struct device_attribute *attr, char *buf)
{
@ -794,6 +824,8 @@ static int uncore_pmu_register(struct intel_uncore_pmu *pmu)
pmu->pmu = (struct pmu) {
.attr_groups = pmu->type->attr_groups,
.task_ctx_nr = perf_invalid_context,
.pmu_enable = uncore_pmu_enable,
.pmu_disable = uncore_pmu_disable,
.event_init = uncore_pmu_event_init,
.add = uncore_pmu_event_add,
.del = uncore_pmu_event_del,

12
arch/x86/events/intel/uncore.h
View file

@ -412,18 +412,6 @@ static inline int uncore_freerunning_hw_config(struct intel_uncore_box *box,
return -EINVAL;
}
static inline void uncore_disable_box(struct intel_uncore_box *box)
{
if (box->pmu->type->ops->disable_box)
box->pmu->type->ops->disable_box(box);
}
static inline void uncore_enable_box(struct intel_uncore_box *box)
{
if (box->pmu->type->ops->enable_box)
box->pmu->type->ops->enable_box(box);
}
static inline void uncore_disable_event(struct intel_uncore_box *box,
struct perf_event *event)
{