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Date: Thu, 1 Apr 2021 17:10:31 -0700
From: kan.liang@...ux.intel.com
To: peterz@...radead.org, mingo@...nel.org,
linux-kernel@...r.kernel.org
Cc: acme@...nel.org, tglx@...utronix.de, bp@...en8.de,
namhyung@...nel.org, jolsa@...hat.com, ak@...ux.intel.com,
yao.jin@...ux.intel.com, alexander.shishkin@...ux.intel.com,
adrian.hunter@...el.com, Kan Liang <kan.liang@...ux.intel.com>
Subject: [PATCH V4 04/25] perf/x86/intel: Hybrid PMU support for perf capabilities
From: Kan Liang <kan.liang@...ux.intel.com>
Some platforms, e.g. Alder Lake, have hybrid architecture. Although most
PMU capabilities are the same, there are still some unique PMU
capabilities for different hybrid PMUs. Perf should register a dedicated
pmu for each hybrid PMU.
Add a new struct x86_hybrid_pmu, which saves the dedicated pmu and
capabilities for each hybrid PMU.
The architecture MSR, MSR_IA32_PERF_CAPABILITIES, only indicates the
architecture features which are available on all hybrid PMUs. The
architecture features are stored in the global x86_pmu.intel_cap.
For Alder Lake, the model-specific features are perf metrics and
PEBS-via-PT. The corresponding bits of the global x86_pmu.intel_cap
should be 0 for these two features. Perf should not use the global
intel_cap to check the features on a hybrid system.
Add a dedicated intel_cap in the x86_hybrid_pmu to store the
model-specific capabilities. Use the dedicated intel_cap to replace
the global intel_cap for thse two features. The dedicated intel_cap
will be set in the following "Add Alder Lake Hybrid support" patch.
Add is_hybrid() to distinguish a hybrid system. ADL may have an
alternative configuration. With that configuration, the
X86_FEATURE_HYBRID_CPU is not set. Perf cannot rely on the feature bit.
The number of hybrid PMUs implies whether it's a hybrid system. The
number will be assigned in the following "Add Alder Lake Hybrid support"
patch as well.
Suggested-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Signed-off-by: Kan Liang <kan.liang@...ux.intel.com>
---
arch/x86/events/core.c | 6 ++++--
arch/x86/events/intel/core.c | 27 ++++++++++++++++++++++-----
arch/x86/events/intel/ds.c | 2 +-
arch/x86/events/perf_event.h | 34 ++++++++++++++++++++++++++++++++++
arch/x86/include/asm/msr-index.h | 3 +++
5 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index e564e96..d3d3c6b 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -1105,8 +1105,9 @@ static void del_nr_metric_event(struct cpu_hw_events *cpuc,
static int collect_event(struct cpu_hw_events *cpuc, struct perf_event *event,
int max_count, int n)
{
+ union perf_capabilities intel_cap = hybrid(cpuc->pmu, intel_cap);
- if (x86_pmu.intel_cap.perf_metrics && add_nr_metric_event(cpuc, event))
+ if (intel_cap.perf_metrics && add_nr_metric_event(cpuc, event))
return -EINVAL;
if (n >= max_count + cpuc->n_metric)
@@ -1582,6 +1583,7 @@ void x86_pmu_stop(struct perf_event *event, int flags)
static void x86_pmu_del(struct perf_event *event, int flags)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+ union perf_capabilities intel_cap = hybrid(cpuc->pmu, intel_cap);
int i;
/*
@@ -1621,7 +1623,7 @@ static void x86_pmu_del(struct perf_event *event, int flags)
}
cpuc->event_constraint[i-1] = NULL;
--cpuc->n_events;
- if (x86_pmu.intel_cap.perf_metrics)
+ if (intel_cap.perf_metrics)
del_nr_metric_event(cpuc, event);
perf_event_update_userpage(event);
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index f116c63..494b9bc 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -3646,6 +3646,15 @@ static inline bool is_mem_loads_aux_event(struct perf_event *event)
return (event->attr.config & INTEL_ARCH_EVENT_MASK) == X86_CONFIG(.event=0x03, .umask=0x82);
}
+static inline bool intel_pmu_has_cap(struct perf_event *event, int idx)
+{
+ union perf_capabilities *intel_cap;
+
+ intel_cap = is_hybrid() ? &hybrid_pmu(event->pmu)->intel_cap :
+ &x86_pmu.intel_cap;
+
+ return test_bit(idx, (unsigned long *)&intel_cap->capabilities);
+}
static int intel_pmu_hw_config(struct perf_event *event)
{
@@ -3712,7 +3721,7 @@ static int intel_pmu_hw_config(struct perf_event *event)
* with a slots event as group leader. When the slots event
* is used in a metrics group, it too cannot support sampling.
*/
- if (x86_pmu.intel_cap.perf_metrics && is_topdown_event(event)) {
+ if (intel_pmu_has_cap(event, PERF_CAP_METRICS_IDX) && is_topdown_event(event)) {
if (event->attr.config1 || event->attr.config2)
return -EINVAL;
@@ -4219,8 +4228,16 @@ static void intel_pmu_cpu_starting(int cpu)
if (x86_pmu.version > 1)
flip_smm_bit(&x86_pmu.attr_freeze_on_smi);
- /* Disable perf metrics if any added CPU doesn't support it. */
- if (x86_pmu.intel_cap.perf_metrics) {
+ /*
+ * Disable perf metrics if any added CPU doesn't support it.
+ *
+ * Turn off the check for a hybrid architecture, because the
+ * architecture MSR, MSR_IA32_PERF_CAPABILITIES, only indicate
+ * the architecture features. The perf metrics is a model-specific
+ * feature for now. The corresponding bit should always be 0 on
+ * a hybrid platform, e.g., Alder Lake.
+ */
+ if (!is_hybrid() && x86_pmu.intel_cap.perf_metrics) {
union perf_capabilities perf_cap;
rdmsrl(MSR_IA32_PERF_CAPABILITIES, perf_cap.capabilities);
@@ -4330,7 +4347,7 @@ static int intel_pmu_check_period(struct perf_event *event, u64 value)
static int intel_pmu_aux_output_match(struct perf_event *event)
{
- if (!x86_pmu.intel_cap.pebs_output_pt_available)
+ if (!intel_pmu_has_cap(event, PERF_CAP_PT_IDX))
return 0;
return is_intel_pt_event(event);
@@ -5770,7 +5787,7 @@ __init int intel_pmu_init(void)
pr_cont("full-width counters, ");
}
- if (x86_pmu.intel_cap.perf_metrics)
+ if (!is_hybrid() && x86_pmu.intel_cap.perf_metrics)
x86_pmu.intel_ctrl |= 1ULL << GLOBAL_CTRL_EN_PERF_METRICS;
return 0;
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index 1bfea8c..9328aa1 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -2205,7 +2205,7 @@ void __init intel_ds_init(void)
}
pr_cont("PEBS fmt4%c%s, ", pebs_type, pebs_qual);
- if (x86_pmu.intel_cap.pebs_output_pt_available) {
+ if (!is_hybrid() && x86_pmu.intel_cap.pebs_output_pt_available) {
pr_cont("PEBS-via-PT, ");
x86_get_pmu(smp_processor_id())->capabilities |= PERF_PMU_CAP_AUX_OUTPUT;
}
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index 3e19ca5..df65012d 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -632,6 +632,29 @@ enum {
x86_lbr_exclusive_max,
};
+struct x86_hybrid_pmu {
+ struct pmu pmu;
+ union perf_capabilities intel_cap;
+};
+
+static __always_inline struct x86_hybrid_pmu *hybrid_pmu(struct pmu *pmu)
+{
+ return container_of(pmu, struct x86_hybrid_pmu, pmu);
+}
+
+/* The number of hybrid PMUs implies whether it's a hybrid system */
+#define is_hybrid() (!!x86_pmu.num_hybrid_pmus)
+
+#define hybrid(_pmu, _field) \
+({ \
+ typeof(x86_pmu._field) __F = x86_pmu._field; \
+ \
+ if (is_hybrid() && (_pmu)) \
+ __F = hybrid_pmu(_pmu)->_field; \
+ \
+ __F; \
+})
+
/*
* struct x86_pmu - generic x86 pmu
*/
@@ -818,6 +841,17 @@ struct x86_pmu {
int (*check_period) (struct perf_event *event, u64 period);
int (*aux_output_match) (struct perf_event *event);
+
+ /*
+ * Hybrid support
+ *
+ * Most PMU capabilities are the same among different hybrid PMUs.
+ * The global x86_pmu saves the architecture capabilities, which
+ * are available for all PMUs. The hybrid_pmu only includes the
+ * unique capabilities.
+ */
+ int num_hybrid_pmus;
+ struct x86_hybrid_pmu *hybrid_pmu;
};
struct x86_perf_task_context_opt {
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 546d6ec..163f5d2 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -185,6 +185,9 @@
#define MSR_PEBS_DATA_CFG 0x000003f2
#define MSR_IA32_DS_AREA 0x00000600
#define MSR_IA32_PERF_CAPABILITIES 0x00000345
+#define PERF_CAP_METRICS_IDX 15
+#define PERF_CAP_PT_IDX 16
+
#define MSR_PEBS_LD_LAT_THRESHOLD 0x000003f6
#define MSR_IA32_RTIT_CTL 0x00000570
--
2.7.4
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