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From:   Ravi Bangoria <ravi.bangoria@linux.ibm.com>
To:     linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Cc:     eranian@google.com, peterz@infradead.org, mpe@ellerman.id.au,
        paulus@samba.org, mingo@redhat.com, acme@kernel.org,
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        alexey.budankov@linux.intel.com, yao.jin@linux.intel.com,
        robert.richter@amd.com, kim.phillips@amd.com, maddy@linux.ibm.com,
        ravi.bangoria@linux.ibm.com,
        Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Subject: [RFC 02/11] perf/core: Data structure to present hazard data
Date:   Mon,  2 Mar 2020 10:53:46 +0530
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From: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>

Introduce new perf sample_type PERF_SAMPLE_PIPELINE_HAZ to request kernel
to provide cpu pipeline hazard data. Also, introduce arch independent
structure 'perf_pipeline_haz_data' to pass hazard data to userspace. This
is generic structure and arch specific data needs to be converted to this
format.

Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
---
 include/linux/perf_event.h            |  7 ++++++
 include/uapi/linux/perf_event.h       | 32 ++++++++++++++++++++++++++-
 kernel/events/core.c                  |  6 +++++
 tools/include/uapi/linux/perf_event.h | 32 ++++++++++++++++++++++++++-
 4 files changed, 75 insertions(+), 2 deletions(-)

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 547773f5894e..d5b606e3c57d 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1001,6 +1001,7 @@ struct perf_sample_data {
 	u64				stack_user_size;
 
 	u64				phys_addr;
+	struct perf_pipeline_haz_data	pipeline_haz;
 } ____cacheline_aligned;
 
 /* default value for data source */
@@ -1021,6 +1022,12 @@ static inline void perf_sample_data_init(struct perf_sample_data *data,
 	data->weight = 0;
 	data->data_src.val = PERF_MEM_NA;
 	data->txn = 0;
+	data->pipeline_haz.itype = PERF_HAZ__ITYPE_NA;
+	data->pipeline_haz.icache = PERF_HAZ__ICACHE_NA;
+	data->pipeline_haz.hazard_stage = PERF_HAZ__PIPE_STAGE_NA;
+	data->pipeline_haz.hazard_reason = PERF_HAZ__HREASON_NA;
+	data->pipeline_haz.stall_stage = PERF_HAZ__PIPE_STAGE_NA;
+	data->pipeline_haz.stall_reason = PERF_HAZ__SREASON_NA;
 }
 
 extern void perf_output_sample(struct perf_output_handle *handle,
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index 377d794d3105..ff252618ca93 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -142,8 +142,9 @@ enum perf_event_sample_format {
 	PERF_SAMPLE_REGS_INTR			= 1U << 18,
 	PERF_SAMPLE_PHYS_ADDR			= 1U << 19,
 	PERF_SAMPLE_AUX				= 1U << 20,
+	PERF_SAMPLE_PIPELINE_HAZ		= 1U << 21,
 
-	PERF_SAMPLE_MAX = 1U << 21,		/* non-ABI */
+	PERF_SAMPLE_MAX = 1U << 22,		/* non-ABI */
 
 	__PERF_SAMPLE_CALLCHAIN_EARLY		= 1ULL << 63, /* non-ABI; internal use */
 };
@@ -870,6 +871,13 @@ enum perf_event_type {
 	 *	{ u64			phys_addr;} && PERF_SAMPLE_PHYS_ADDR
 	 *	{ u64			size;
 	 *	  char			data[size]; } && PERF_SAMPLE_AUX
+	 *	{ u8			itype;
+	 *	  u8			icache;
+	 *	  u8			hazard_stage;
+	 *	  u8			hazard_reason;
+	 *	  u8			stall_stage;
+	 *	  u8			stall_reason;
+	 *	  u16			pad;} && PERF_SAMPLE_PIPELINE_HAZ
 	 * };
 	 */
 	PERF_RECORD_SAMPLE			= 9,
@@ -1185,4 +1193,26 @@ struct perf_branch_entry {
 		reserved:40;
 };
 
+struct perf_pipeline_haz_data {
+	/* Instruction/Opcode type: Load, Store, Branch .... */
+	__u8	itype;
+	/* Instruction Cache source */
+	__u8	icache;
+	/* Instruction suffered hazard in pipeline stage */
+	__u8	hazard_stage;
+	/* Hazard reason */
+	__u8	hazard_reason;
+	/* Instruction suffered stall in pipeline stage */
+	__u8	stall_stage;
+	/* Stall reason */
+	__u8	stall_reason;
+	__u16	pad;
+};
+
+#define PERF_HAZ__ITYPE_NA	0x0
+#define PERF_HAZ__ICACHE_NA	0x0
+#define PERF_HAZ__PIPE_STAGE_NA	0x0
+#define PERF_HAZ__HREASON_NA	0x0
+#define PERF_HAZ__SREASON_NA	0x0
+
 #endif /* _UAPI_LINUX_PERF_EVENT_H */
diff --git a/kernel/events/core.c b/kernel/events/core.c
index e453589da97c..d00037c77ccf 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1754,6 +1754,9 @@ static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
 	if (sample_type & PERF_SAMPLE_PHYS_ADDR)
 		size += sizeof(data->phys_addr);
 
+	if (sample_type & PERF_SAMPLE_PIPELINE_HAZ)
+		size += sizeof(data->pipeline_haz);
+
 	event->header_size = size;
 }
 
@@ -6712,6 +6715,9 @@ void perf_output_sample(struct perf_output_handle *handle,
 			perf_aux_sample_output(event, handle, data);
 	}
 
+	if (sample_type & PERF_SAMPLE_PIPELINE_HAZ)
+		perf_output_put(handle, data->pipeline_haz);
+
 	if (!event->attr.watermark) {
 		int wakeup_events = event->attr.wakeup_events;
 
diff --git a/tools/include/uapi/linux/perf_event.h b/tools/include/uapi/linux/perf_event.h
index 377d794d3105..ff252618ca93 100644
--- a/tools/include/uapi/linux/perf_event.h
+++ b/tools/include/uapi/linux/perf_event.h
@@ -142,8 +142,9 @@ enum perf_event_sample_format {
 	PERF_SAMPLE_REGS_INTR			= 1U << 18,
 	PERF_SAMPLE_PHYS_ADDR			= 1U << 19,
 	PERF_SAMPLE_AUX				= 1U << 20,
+	PERF_SAMPLE_PIPELINE_HAZ		= 1U << 21,
 
-	PERF_SAMPLE_MAX = 1U << 21,		/* non-ABI */
+	PERF_SAMPLE_MAX = 1U << 22,		/* non-ABI */
 
 	__PERF_SAMPLE_CALLCHAIN_EARLY		= 1ULL << 63, /* non-ABI; internal use */
 };
@@ -870,6 +871,13 @@ enum perf_event_type {
 	 *	{ u64			phys_addr;} && PERF_SAMPLE_PHYS_ADDR
 	 *	{ u64			size;
 	 *	  char			data[size]; } && PERF_SAMPLE_AUX
+	 *	{ u8			itype;
+	 *	  u8			icache;
+	 *	  u8			hazard_stage;
+	 *	  u8			hazard_reason;
+	 *	  u8			stall_stage;
+	 *	  u8			stall_reason;
+	 *	  u16			pad;} && PERF_SAMPLE_PIPELINE_HAZ
 	 * };
 	 */
 	PERF_RECORD_SAMPLE			= 9,
@@ -1185,4 +1193,26 @@ struct perf_branch_entry {
 		reserved:40;
 };
 
+struct perf_pipeline_haz_data {
+	/* Instruction/Opcode type: Load, Store, Branch .... */
+	__u8	itype;
+	/* Instruction Cache source */
+	__u8	icache;
+	/* Instruction suffered hazard in pipeline stage */
+	__u8	hazard_stage;
+	/* Hazard reason */
+	__u8	hazard_reason;
+	/* Instruction suffered stall in pipeline stage */
+	__u8	stall_stage;
+	/* Stall reason */
+	__u8	stall_reason;
+	__u16	pad;
+};
+
+#define PERF_HAZ__ITYPE_NA	0x0
+#define PERF_HAZ__ICACHE_NA	0x0
+#define PERF_HAZ__PIPE_STAGE_NA	0x0
+#define PERF_HAZ__HREASON_NA	0x0
+#define PERF_HAZ__SREASON_NA	0x0
+
 #endif /* _UAPI_LINUX_PERF_EVENT_H */
-- 
2.21.1