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