Commit c315669e authored by Athira Rajeev's avatar Athira Rajeev Committed by Michael Ellerman
Browse files

selftests/powerpc/pmu: Add support for perf sampling tests 



Add support functions for enabling perf sampling test in a new folder
"sampling_tests" under "selftests/powerpc/pmu". This includes support
functions for allocating and processing the mmap buffer. These functions
are added/defined in "sampling_tests/misc.*" files.

Also updates the corresponding Makefiles in "selftests/powerpc" and
"sampling_tests" folder.

Signed-off-by: default avatarAthira Rajeev <atrajeev@linux.vnet.ibm.com>
[mpe: Drop unneeded bits from the Makefile]
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220127072012.662451-3-kjain@linux.ibm.com
parent f961e20f

tools/testing/selftests/powerpc/pmu/Makefile

+9 −2
Original line number Diff line number Diff line
@@ -8,7 +8,7 @@ EXTRA_SOURCES := ../harness.c event.c lib.c ../utils.c 
top_srcdir = ../../../../..

include ../../lib.mk



all: $(TEST_GEN_PROGS) ebb

all: $(TEST_GEN_PROGS) ebb sampling_tests



$(TEST_GEN_PROGS): $(EXTRA_SOURCES)
@@ -26,25 +26,32 @@ DEFAULT_RUN_TESTS := $(RUN_TESTS) 
override define RUN_TESTS

	$(DEFAULT_RUN_TESTS)

	TARGET=ebb; BUILD_TARGET=$$OUTPUT/$$TARGET; $(MAKE) OUTPUT=$$BUILD_TARGET -C $$TARGET run_tests

	TARGET=sampling_tests; BUILD_TARGET=$$OUTPUT/$$TARGET; $(MAKE) OUTPUT=$$BUILD_TARGET -C $$TARGET run_tests

endef



DEFAULT_EMIT_TESTS := $(EMIT_TESTS)

override define EMIT_TESTS

	$(DEFAULT_EMIT_TESTS)

	TARGET=ebb; BUILD_TARGET=$$OUTPUT/$$TARGET; $(MAKE) OUTPUT=$$BUILD_TARGET -s -C $$TARGET emit_tests

	TARGET=sampling_tests; BUILD_TARGET=$$OUTPUT/$$TARGET; $(MAKE) OUTPUT=$$BUILD_TARGET -s -C $$TARGET emit_tests

endef



DEFAULT_INSTALL_RULE := $(INSTALL_RULE)

override define INSTALL_RULE

	$(DEFAULT_INSTALL_RULE)

	TARGET=ebb; BUILD_TARGET=$$OUTPUT/$$TARGET; $(MAKE) OUTPUT=$$BUILD_TARGET -C $$TARGET install

	TARGET=sampling_tests; BUILD_TARGET=$$OUTPUT/$$TARGET; $(MAKE) OUTPUT=$$BUILD_TARGET -C $$TARGET install

endef



clean:

	$(RM) $(TEST_GEN_PROGS) $(OUTPUT)/loop.o

	TARGET=ebb; BUILD_TARGET=$$OUTPUT/$$TARGET; $(MAKE) OUTPUT=$$BUILD_TARGET -C $$TARGET clean

	TARGET=sampling_tests; BUILD_TARGET=$$OUTPUT/$$TARGET; $(MAKE) OUTPUT=$$BUILD_TARGET -C $$TARGET clean



ebb:

	TARGET=$@; BUILD_TARGET=$$OUTPUT/$$TARGET; mkdir -p $$BUILD_TARGET; $(MAKE) OUTPUT=$$BUILD_TARGET -k -C $$TARGET all



.PHONY: all run_tests clean ebb
 
sampling_tests:

	TARGET=$@; BUILD_TARGET=$$OUTPUT/$$TARGET; mkdir -p $$BUILD_TARGET; $(MAKE) OUTPUT=$$BUILD_TARGET -k -C $$TARGET all



.PHONY: all run_tests clean ebb sampling_tests

tools/testing/selftests/powerpc/pmu/sampling_tests/Makefile

0 → 100644
+7 −0
Original line number Diff line number Diff line 
# SPDX-License-Identifier: GPL-2.0

CFLAGS += -m64



top_srcdir = ../../../../../..

include ../../../lib.mk



$(TEST_GEN_PROGS): ../../harness.c ../../utils.c ../event.c ../lib.c misc.c misc.h

tools/testing/selftests/powerpc/pmu/sampling_tests/misc.c

0 → 100644
+105 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/*

 * Copyright 2022, Athira Rajeev, IBM Corp.

 */



#include <unistd.h>

#include <sys/syscall.h>

#include <string.h>

#include <stdio.h>

#include <sys/ioctl.h>

#include <sys/mman.h>

#include <stdlib.h>

#include <ctype.h>



#include "misc.h"



#define PAGE_SIZE               sysconf(_SC_PAGESIZE)



/*

 * Allocate mmap buffer of "mmap_pages" number of

 * pages.

 */

void *event_sample_buf_mmap(int fd, int mmap_pages)

{

	size_t page_size = sysconf(_SC_PAGESIZE);

	size_t mmap_size;

	void *buff;



	if (mmap_pages <= 0)

		return NULL;



	if (fd <= 0)

		return NULL;



	mmap_size =  page_size * (1 + mmap_pages);

	buff = mmap(NULL, mmap_size,

		PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);



	if (buff == MAP_FAILED) {

		perror("mmap() failed.");

		return NULL;

	}

	return buff;

}



/*

 * Post process the mmap buffer.

 * - If sample_count != NULL then return count of total

 *   number of samples present in the mmap buffer.

 * - If sample_count == NULL then return the address

 *   of first sample from the mmap buffer

 */

void *__event_read_samples(void *sample_buff, size_t *size, u64 *sample_count)

{

	size_t page_size = sysconf(_SC_PAGESIZE);

	struct perf_event_header *header = sample_buff + page_size;

	struct perf_event_mmap_page *metadata_page = sample_buff;

	unsigned long data_head, data_tail;



	/*

	 * PERF_RECORD_SAMPLE:

	 * struct {

	 *     struct perf_event_header hdr;

	 *     u64 data[];

	 * };

	 */



	data_head = metadata_page->data_head;

	/* sync memory before reading sample */

	mb();

	data_tail = metadata_page->data_tail;



	/* Check for sample_count */

	if (sample_count)

		*sample_count = 0;



	while (1) {

		/*

		 * Reads the mmap data buffer by moving

		 * the data_tail to know the last read data.

		 * data_head points to head in data buffer.

		 * refer "struct perf_event_mmap_page" in

		 * "include/uapi/linux/perf_event.h".

		 */

		if (data_head - data_tail < sizeof(header))

			return NULL;



		data_tail += sizeof(header);

		if (header->type == PERF_RECORD_SAMPLE) {

			*size = (header->size - sizeof(header));

			if (!sample_count)

				return sample_buff + page_size + data_tail;

			data_tail += *size;

			*sample_count += 1;

		} else {

			*size = (header->size - sizeof(header));

			if ((metadata_page->data_tail + *size) > metadata_page->data_head)

				data_tail = metadata_page->data_head;

			else

				data_tail += *size;

		}

		header = (struct perf_event_header *)((void *)header + header->size);

	}

	return NULL;

}

tools/testing/selftests/powerpc/pmu/sampling_tests/misc.h

0 → 100644
+9 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0-only */

/*

 * Copyright 2022, Athira Rajeev, IBM Corp.

 */



#include "../event.h"



void *event_sample_buf_mmap(int fd, int mmap_pages);

void *__event_read_samples(void *sample_buff, size_t *size, u64 *sample_count);