src/map_perf_ring.c

// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
/* Copyright (C) 2018 Netronome Systems, Inc. */
/* This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 */
#include <errno.h>
#include <fcntl.h>
#include <bpf/libbpf.h>
#include <poll.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <linux/bpf.h>
#include <linux/perf_event.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/syscall.h>

#include <bpf/bpf.h>

#include "main.h"

#define MMAP_PAGE_CNT	16

static volatile bool stop;

struct event_ring_info {
	int fd;
	int key;
	unsigned int cpu;
	void *mem;
};

struct perf_event_sample {
	struct perf_event_header header;
	__u64 time;
	__u32 size;
	unsigned char data[];
};

struct perf_event_lost {
	struct perf_event_header header;
	__u64 id;
	__u64 lost;
};

static void int_exit(int signo)
{
	fprintf(stderr, "Stopping...\n");
	stop = true;
}

struct event_pipe_ctx {
	bool all_cpus;
	int cpu;
	int idx;
};

static enum bpf_perf_event_ret
print_bpf_output(void *private_data, int cpu, struct perf_event_header *event)
{
	struct perf_event_sample *e = container_of(event,
						   struct perf_event_sample,
						   header);
	struct perf_event_lost *lost = container_of(event,
						    struct perf_event_lost,
						    header);
	struct event_pipe_ctx *ctx = private_data;
	int idx = ctx->all_cpus ? cpu : ctx->idx;

	if (json_output) {
		jsonw_start_object(json_wtr);
		jsonw_name(json_wtr, "type");
		jsonw_uint(json_wtr, e->header.type);
		jsonw_name(json_wtr, "cpu");
		jsonw_uint(json_wtr, cpu);
		jsonw_name(json_wtr, "index");
		jsonw_uint(json_wtr, idx);
		if (e->header.type == PERF_RECORD_SAMPLE) {
			jsonw_name(json_wtr, "timestamp");
			jsonw_uint(json_wtr, e->time);
			jsonw_name(json_wtr, "data");
			print_data_json(e->data, e->size);
		} else if (e->header.type == PERF_RECORD_LOST) {
			jsonw_name(json_wtr, "lost");
			jsonw_start_object(json_wtr);
			jsonw_name(json_wtr, "id");
			jsonw_uint(json_wtr, lost->id);
			jsonw_name(json_wtr, "count");
			jsonw_uint(json_wtr, lost->lost);
			jsonw_end_object(json_wtr);
		}
		jsonw_end_object(json_wtr);
	} else {
		if (e->header.type == PERF_RECORD_SAMPLE) {
			printf("== @%lld.%09lld CPU: %d index: %d =====\n",
			       e->time / 1000000000ULL, e->time % 1000000000ULL,
			       cpu, idx);
			fprint_hex(stdout, e->data, e->size, " ");
			printf("\n");
		} else if (e->header.type == PERF_RECORD_LOST) {
			printf("lost %lld events\n", lost->lost);
		} else {
			printf("unknown event type=%d size=%d\n",
			       e->header.type, e->header.size);
		}
	}

	return LIBBPF_PERF_EVENT_CONT;
}

int do_event_pipe(int argc, char **argv)
{
	struct perf_event_attr perf_attr = {
		.sample_type = PERF_SAMPLE_RAW | PERF_SAMPLE_TIME,
		.type = PERF_TYPE_SOFTWARE,
		.config = PERF_COUNT_SW_BPF_OUTPUT,
		.sample_period = 1,
		.wakeup_events = 1,
	};
	struct bpf_map_info map_info = {};
	LIBBPF_OPTS(perf_buffer_raw_opts, opts);
	struct event_pipe_ctx ctx = {
		.all_cpus = true,
		.cpu = -1,
		.idx = -1,
	};
	struct perf_buffer *pb;
	__u32 map_info_len;
	int err, map_fd;

	map_info_len = sizeof(map_info);
	map_fd = map_parse_fd_and_info(&argc, &argv, &map_info, &map_info_len);
	if (map_fd < 0)
		return -1;

	if (map_info.type != BPF_MAP_TYPE_PERF_EVENT_ARRAY) {
		p_err("map is not a perf event array");
		goto err_close_map;
	}

	while (argc) {
		if (argc < 2) {
			BAD_ARG();
			goto err_close_map;
		}

		if (is_prefix(*argv, "cpu")) {
			char *endptr;

			NEXT_ARG();
			ctx.cpu = strtoul(*argv, &endptr, 0);
			if (*endptr) {
				p_err("can't parse %s as CPU ID", *argv);
				goto err_close_map;
			}

			NEXT_ARG();
		} else if (is_prefix(*argv, "index")) {
			char *endptr;

			NEXT_ARG();
			ctx.idx = strtoul(*argv, &endptr, 0);
			if (*endptr) {
				p_err("can't parse %s as index", *argv);
				goto err_close_map;
			}

			NEXT_ARG();
		} else {
			BAD_ARG();
			goto err_close_map;
		}

		ctx.all_cpus = false;
	}

	if (!ctx.all_cpus) {
		if (ctx.idx == -1 || ctx.cpu == -1) {
			p_err("cpu and index must be specified together");
			goto err_close_map;
		}
	} else {
		ctx.cpu = 0;
		ctx.idx = 0;
	}

	opts.cpu_cnt = ctx.all_cpus ? 0 : 1;
	opts.cpus = &ctx.cpu;
	opts.map_keys = &ctx.idx;
	pb = perf_buffer__new_raw(map_fd, MMAP_PAGE_CNT, &perf_attr,
				  print_bpf_output, &ctx, &opts);
	err = libbpf_get_error(pb);
	if (err) {
		p_err("failed to create perf buffer: %s (%d)",
		      strerror(err), err);
		goto err_close_map;
	}

	signal(SIGINT, int_exit);
	signal(SIGHUP, int_exit);
	signal(SIGTERM, int_exit);

	if (json_output)
		jsonw_start_array(json_wtr);

	while (!stop) {
		err = perf_buffer__poll(pb, 200);
		if (err < 0 && err != -EINTR) {
			p_err("perf buffer polling failed: %s (%d)",
			      strerror(err), err);
			goto err_close_pb;
		}
	}

	if (json_output)
		jsonw_end_array(json_wtr);

	perf_buffer__free(pb);
	close(map_fd);

	return 0;

err_close_pb:
	perf_buffer__free(pb);
err_close_map:
	close(map_fd);
	return -1;
}