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
17 static 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
28 const 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 };
42 const int num_colors = ARRAY_SIZE(color);
43
44 const char nocolor[] = "\033[00m";
45
46 const char *sym[] = {
47 " ",
48 " ",
49 ".",
50 ".",
51 "*",
52 "*",
53 "o",
54 "o",
55 "O",
56 "O",
57 "#",
58 "#",
59 };
60
61 bool full_range = false;
62 bool text_only = false;
63
64 static 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
74 static 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
107 int 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
177 cleanup:
178 for (j--; j >= 0; j--)
179 bpf_link__destroy(links[j]);
180
181 bpf_object__close(obj);
182 return 0;
183 }
184
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