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
clear_stats(int fd)18 static 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
29 const 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 };
43 const int num_colors = ARRAY_SIZE(color);
44
45 const char nocolor[] = "\033[00m";
46
47 const char *sym[] = {
48 " ",
49 " ",
50 ".",
51 ".",
52 "*",
53 "*",
54 "o",
55 "o",
56 "O",
57 "O",
58 "#",
59 "#",
60 };
61
62 bool full_range = false;
63 bool text_only = false;
64
print_banner(void)65 static 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
print_hist(int fd)75 static 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
main(int ac,char ** argv)108 int main(int ac, char **argv)
109 {
110 struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
111 struct bpf_link *links[2];
112 struct bpf_program *prog;
113 struct bpf_object *obj;
114 char filename[256];
115 int map_fd, i, j = 0;
116
117 for (i = 1; i < ac; i++) {
118 if (strcmp(argv[i], "-a") == 0) {
119 full_range = true;
120 } else if (strcmp(argv[i], "-t") == 0) {
121 text_only = true;
122 } else if (strcmp(argv[i], "-h") == 0) {
123 printf("Usage:\n"
124 " -a display wider latency range\n"
125 " -t text only\n");
126 return 1;
127 }
128 }
129
130 if (setrlimit(RLIMIT_MEMLOCK, &r)) {
131 perror("setrlimit(RLIMIT_MEMLOCK)");
132 return 1;
133 }
134
135 snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
136 obj = bpf_object__open_file(filename, NULL);
137 if (libbpf_get_error(obj)) {
138 fprintf(stderr, "ERROR: opening BPF object file failed\n");
139 return 0;
140 }
141
142 /* load BPF program */
143 if (bpf_object__load(obj)) {
144 fprintf(stderr, "ERROR: loading BPF object file failed\n");
145 goto cleanup;
146 }
147
148 map_fd = bpf_object__find_map_fd_by_name(obj, "lat_map");
149 if (map_fd < 0) {
150 fprintf(stderr, "ERROR: finding a map in obj file failed\n");
151 goto cleanup;
152 }
153
154 bpf_object__for_each_program(prog, obj) {
155 links[j] = bpf_program__attach(prog);
156 if (libbpf_get_error(links[j])) {
157 fprintf(stderr, "ERROR: bpf_program__attach failed\n");
158 links[j] = NULL;
159 goto cleanup;
160 }
161 j++;
162 }
163
164 printf(" heatmap of IO latency\n");
165 if (text_only)
166 printf(" %s", sym[num_colors - 1]);
167 else
168 printf(" %s %s", color[num_colors - 1], nocolor);
169 printf(" - many events with this latency\n");
170
171 if (text_only)
172 printf(" %s", sym[0]);
173 else
174 printf(" %s %s", color[0], nocolor);
175 printf(" - few events\n");
176
177 for (i = 0; ; i++) {
178 if (i % 20 == 0)
179 print_banner();
180 print_hist(map_fd);
181 sleep(2);
182 }
183
184 cleanup:
185 for (j--; j >= 0; j--)
186 bpf_link__destroy(links[j]);
187
188 bpf_object__close(obj);
189 return 0;
190 }
191