linux-kernel - [PATCH V5 21/25] perf: Introduce PERF_TYPE_HARDWARE_PMU and PERF_TYPE_HW_CACHE

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Date:   Mon,  5 Apr 2021 08:11:03 -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, ricardo.neri-calderon@...ux.intel.com,
        Kan Liang <kan.liang@...ux.intel.com>
Subject: [PATCH V5 21/25] perf: Introduce PERF_TYPE_HARDWARE_PMU and PERF_TYPE_HW_CACHE_PMU

From: Kan Liang <kan.liang@...ux.intel.com>

Current Hardware events and Hardware cache events have special perf
types, PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE. The two types don't
pass the PMU type in the user interface. For a hybrid system, the perf
subsystem doesn't know which PMU the events belong to. The first capable
PMU will always be assigned to the events. The events never get a chance
to run on the other capable PMUs.

Add a PMU aware version PERF_TYPE_HARDWARE_PMU and
PERF_TYPE_HW_CACHE_PMU. The PMU type ID is stored at attr.config[40:32].
Support the new types for X86.

Suggested-by: Andi Kleen <ak@...ux.intel.com>
Reviewed-by: Andi Kleen <ak@...ux.intel.com>
Signed-off-by: Kan Liang <kan.liang@...ux.intel.com>
---
 arch/x86/events/core.c          | 10 ++++++++--
 include/uapi/linux/perf_event.h | 26 ++++++++++++++++++++++++++
 kernel/events/core.c            | 14 +++++++++++++-
 3 files changed, 47 insertions(+), 3 deletions(-)

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 09922ee..f8d1222 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -488,7 +488,7 @@ int x86_setup_perfctr(struct perf_event *event)
 	if (attr->type == event->pmu->type)
 		return x86_pmu_extra_regs(event->attr.config, event);
 
-	if (attr->type == PERF_TYPE_HW_CACHE)
+	if ((attr->type == PERF_TYPE_HW_CACHE) || (attr->type == PERF_TYPE_HW_CACHE_PMU))
 		return set_ext_hw_attr(hwc, event);
 
 	if (attr->config >= x86_pmu.max_events)
@@ -2452,9 +2452,15 @@ static int x86_pmu_event_init(struct perf_event *event)
 
 	if ((event->attr.type != event->pmu->type) &&
 	    (event->attr.type != PERF_TYPE_HARDWARE) &&
-	    (event->attr.type != PERF_TYPE_HW_CACHE))
+	    (event->attr.type != PERF_TYPE_HW_CACHE) &&
+	    (event->attr.type != PERF_TYPE_HARDWARE_PMU) &&
+	    (event->attr.type != PERF_TYPE_HW_CACHE_PMU))
 		return -ENOENT;
 
+	if ((event->attr.type == PERF_TYPE_HARDWARE_PMU) ||
+	    (event->attr.type == PERF_TYPE_HW_CACHE_PMU))
+		event->attr.config &= PERF_HW_CACHE_EVENT_MASK;
+
 	if (is_hybrid() && (event->cpu != -1)) {
 		pmu = hybrid_pmu(event->pmu);
 		if (!cpumask_test_cpu(event->cpu, &pmu->supported_cpus))
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index ad15e40..c0a511e 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -33,6 +33,8 @@ enum perf_type_id {
 	PERF_TYPE_HW_CACHE			= 3,
 	PERF_TYPE_RAW				= 4,
 	PERF_TYPE_BREAKPOINT			= 5,
+	PERF_TYPE_HARDWARE_PMU			= 6,
+	PERF_TYPE_HW_CACHE_PMU			= 7,
 
 	PERF_TYPE_MAX,				/* non-ABI */
 };
@@ -95,6 +97,30 @@ enum perf_hw_cache_op_result_id {
 };
 
 /*
+ * attr.config layout for type PERF_TYPE_HARDWARE* and PERF_TYPE_HW_CACHE*
+ * PERF_TYPE_HARDWARE:		0xAA
+ *				AA: hardware event ID
+ * PERF_TYPE_HW_CACHE:		0xCCBBAA
+ *				AA: hardware cache ID
+ *				BB: hardware cache op ID
+ *				CC: hardware cache op result ID
+ * PERF_TYPE_HARDWARE_PMU:	0xDD000000AA
+ *				AA: hardware event ID
+ *				DD: PMU type ID
+ * PERF_TYPE_HW_CACHE_PMU:	0xDD00CCBBAA
+ *				AA: hardware cache ID
+ *				BB: hardware cache op ID
+ *				CC: hardware cache op result ID
+ *				DD: PMU type ID
+ */
+#define PERF_HW_CACHE_ID_SHIFT			0
+#define PERF_HW_CACHE_OP_ID_SHIFT		8
+#define PERF_HW_CACHE_OP_RESULT_ID_SHIFT	16
+#define PERF_HW_CACHE_EVENT_MASK		0xffffff
+
+#define PERF_PMU_TYPE_SHIFT			32
+
+/*
  * Special "software" events provided by the kernel, even if the hardware
  * does not support performance events. These events measure various
  * physical and sw events of the kernel (and allow the profiling of them as
diff --git a/kernel/events/core.c b/kernel/events/core.c
index f079431..b8ab756 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -11093,6 +11093,14 @@ static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
 	return ret;
 }
 
+static bool perf_event_is_hw_pmu_type(struct perf_event *event)
+{
+	int type = event->attr.type;
+
+	return type == PERF_TYPE_HARDWARE_PMU ||
+	       type == PERF_TYPE_HW_CACHE_PMU;
+}
+
 static struct pmu *perf_init_event(struct perf_event *event)
 {
 	int idx, type, ret;
@@ -11116,13 +11124,17 @@ static struct pmu *perf_init_event(struct perf_event *event)
 	if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE)
 		type = PERF_TYPE_RAW;
 
+	if (perf_event_is_hw_pmu_type(event))
+		type = event->attr.config >> PERF_PMU_TYPE_SHIFT;
+
 again:
 	rcu_read_lock();
 	pmu = idr_find(&pmu_idr, type);
 	rcu_read_unlock();
 	if (pmu) {
 		ret = perf_try_init_event(pmu, event);
-		if (ret == -ENOENT && event->attr.type != type) {
+		if (ret == -ENOENT && event->attr.type != type &&
+		    !perf_event_is_hw_pmu_type(event)) {
 			type = event->attr.type;
 			goto again;
 		}
-- 
2.7.4