1// SPDX-License-Identifier: GPL-2.0-only
  2/* Copyright (c) 2013-2015 PLUMgrid, http://plumgrid.com
  3 */
  4#include <stdio.h>
  5#include <stdlib.h>
  6#include <signal.h>
  7#include <unistd.h>
  8#include <stdbool.h>
  9#include <string.h>
 10#include <sys/resource.h>
 11
 12#include <bpf/bpf.h>
 13#include <bpf/libbpf.h>
 14#include "bpf_util.h"
 15
 16#define SLOTS 100
 17
 18static void clear_stats(int fd)
 19{
 20	unsigned int nr_cpus = bpf_num_possible_cpus();
 21	__u64 values[nr_cpus];
 22	__u32 key;
 23
 24	memset(values, 0, sizeof(values));
 25	for (key = 0; key < SLOTS; key++)
 26		bpf_map_update_elem(fd, &key, values, BPF_ANY);
 27}
 28
 29const char *color[] = {
 30	"\033[48;5;255m",
 31	"\033[48;5;252m",
 32	"\033[48;5;250m",
 33	"\033[48;5;248m",
 34	"\033[48;5;246m",
 35	"\033[48;5;244m",
 36	"\033[48;5;242m",
 37	"\033[48;5;240m",
 38	"\033[48;5;238m",
 39	"\033[48;5;236m",
 40	"\033[48;5;234m",
 41	"\033[48;5;232m",
 42};
 43const int num_colors = ARRAY_SIZE(color);
 44
 45const char nocolor[] = "\033[00m";
 46
 47const char *sym[] = {
 48	" ",
 49	" ",
 50	".",
 51	".",
 52	"*",
 53	"*",
 54	"o",
 55	"o",
 56	"O",
 57	"O",
 58	"#",
 59	"#",
 60};
 61
 62bool full_range = false;
 63bool text_only = false;
 64
 65static void print_banner(void)
 66{
 67	if (full_range)
 68		printf("|1ns     |10ns     |100ns    |1us      |10us     |100us"
 69		       "    |1ms      |10ms     |100ms    |1s       |10s\n");
 70	else
 71		printf("|1us      |10us     |100us    |1ms      |10ms     "
 72		       "|100ms    |1s       |10s\n");
 73}
 74
 75static void print_hist(int fd)
 76{
 77	unsigned int nr_cpus = bpf_num_possible_cpus();
 78	__u64 total_events = 0;
 79	long values[nr_cpus];
 80	__u64 max_cnt = 0;
 81	__u64 cnt[SLOTS];
 82	__u64 value;
 83	__u32 key;
 84	int i;
 85
 86	for (key = 0; key < SLOTS; key++) {
 87		bpf_map_lookup_elem(fd, &key, values);
 88		value = 0;
 89		for (i = 0; i < nr_cpus; i++)
 90			value += values[i];
 91		cnt[key] = value;
 92		total_events += value;
 93		if (value > max_cnt)
 94			max_cnt = value;
 95	}
 96	clear_stats(fd);
 97	for (key = full_range ? 0 : 29; key < SLOTS; key++) {
 98		int c = num_colors * cnt[key] / (max_cnt + 1);
 99
100		if (text_only)
101			printf("%s", sym[c]);
102		else
103			printf("%s %s", color[c], nocolor);
104	}
105	printf(" # %lld\n", total_events);
106}
107
108int main(int ac, char **argv)
109{
110	struct bpf_link *links[2];
111	struct bpf_program *prog;
112	struct bpf_object *obj;
113	char filename[256];
114	int map_fd, i, j = 0;
115
116	for (i = 1; i < ac; i++) {
117		if (strcmp(argv[i], "-a") == 0) {
118			full_range = true;
119		} else if (strcmp(argv[i], "-t") == 0) {
120			text_only = true;
121		} else if (strcmp(argv[i], "-h") == 0) {
122			printf("Usage:\n"
123			       "  -a display wider latency range\n"
124			       "  -t text only\n");
125			return 1;
126		}
127	}
128
129	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
130	obj = bpf_object__open_file(filename, NULL);
131	if (libbpf_get_error(obj)) {
132		fprintf(stderr, "ERROR: opening BPF object file failed\n");
133		return 0;
134	}
135
136	/* load BPF program */
137	if (bpf_object__load(obj)) {
138		fprintf(stderr, "ERROR: loading BPF object file failed\n");
139		goto cleanup;
140	}
141
142	map_fd = bpf_object__find_map_fd_by_name(obj, "lat_map");
143	if (map_fd < 0) {
144		fprintf(stderr, "ERROR: finding a map in obj file failed\n");
145		goto cleanup;
146	}
147
148	bpf_object__for_each_program(prog, obj) {
149		links[j] = bpf_program__attach(prog);
150		if (libbpf_get_error(links[j])) {
151			fprintf(stderr, "ERROR: bpf_program__attach failed\n");
152			links[j] = NULL;
153			goto cleanup;
154		}
155		j++;
156	}
157
158	printf("  heatmap of IO latency\n");
159	if (text_only)
160		printf("  %s", sym[num_colors - 1]);
161	else
162		printf("  %s %s", color[num_colors - 1], nocolor);
163	printf(" - many events with this latency\n");
164
165	if (text_only)
166		printf("  %s", sym[0]);
167	else
168		printf("  %s %s", color[0], nocolor);
169	printf(" - few events\n");
170
171	for (i = 0; ; i++) {
172		if (i % 20 == 0)
173			print_banner();
174		print_hist(map_fd);
175		sleep(2);
176	}
177
178cleanup:
179	for (j--; j >= 0; j--)
180		bpf_link__destroy(links[j]);
181
182	bpf_object__close(obj);
183	return 0;
184}