1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
|
// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2013-2015 PLUMgrid, http://plumgrid.com
*/
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include <stdbool.h>
#include <string.h>
#include <sys/resource.h>
#include <bpf/bpf.h>
#include <bpf/libbpf.h>
#include "bpf_util.h"
#define SLOTS 100
static void clear_stats(int fd)
{
unsigned int nr_cpus = bpf_num_possible_cpus();
__u64 values[nr_cpus];
__u32 key;
memset(values, 0, sizeof(values));
for (key = 0; key < SLOTS; key++)
bpf_map_update_elem(fd, &key, values, BPF_ANY);
}
const char *color[] = {
"\033[48;5;255m",
"\033[48;5;252m",
"\033[48;5;250m",
"\033[48;5;248m",
"\033[48;5;246m",
"\033[48;5;244m",
"\033[48;5;242m",
"\033[48;5;240m",
"\033[48;5;238m",
"\033[48;5;236m",
"\033[48;5;234m",
"\033[48;5;232m",
};
const int num_colors = ARRAY_SIZE(color);
const char nocolor[] = "\033[00m";
const char *sym[] = {
" ",
" ",
".",
".",
"*",
"*",
"o",
"o",
"O",
"O",
"#",
"#",
};
bool full_range = false;
bool text_only = false;
static void print_banner(void)
{
if (full_range)
printf("|1ns |10ns |100ns |1us |10us |100us"
" |1ms |10ms |100ms |1s |10s\n");
else
printf("|1us |10us |100us |1ms |10ms "
"|100ms |1s |10s\n");
}
static void print_hist(int fd)
{
unsigned int nr_cpus = bpf_num_possible_cpus();
__u64 total_events = 0;
long values[nr_cpus];
__u64 max_cnt = 0;
__u64 cnt[SLOTS];
__u64 value;
__u32 key;
int i;
for (key = 0; key < SLOTS; key++) {
bpf_map_lookup_elem(fd, &key, values);
value = 0;
for (i = 0; i < nr_cpus; i++)
value += values[i];
cnt[key] = value;
total_events += value;
if (value > max_cnt)
max_cnt = value;
}
clear_stats(fd);
for (key = full_range ? 0 : 29; key < SLOTS; key++) {
int c = num_colors * cnt[key] / (max_cnt + 1);
if (text_only)
printf("%s", sym[c]);
else
printf("%s %s", color[c], nocolor);
}
printf(" # %lld\n", total_events);
}
int main(int ac, char **argv)
{
struct rlimit r = {1024*1024, RLIM_INFINITY};
struct bpf_link *links[2];
struct bpf_program *prog;
struct bpf_object *obj;
char filename[256];
int map_fd, i, j = 0;
for (i = 1; i < ac; i++) {
if (strcmp(argv[i], "-a") == 0) {
full_range = true;
} else if (strcmp(argv[i], "-t") == 0) {
text_only = true;
} else if (strcmp(argv[i], "-h") == 0) {
printf("Usage:\n"
" -a display wider latency range\n"
" -t text only\n");
return 1;
}
}
if (setrlimit(RLIMIT_MEMLOCK, &r)) {
perror("setrlimit(RLIMIT_MEMLOCK)");
return 1;
}
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
obj = bpf_object__open_file(filename, NULL);
if (libbpf_get_error(obj)) {
fprintf(stderr, "ERROR: opening BPF object file failed\n");
return 0;
}
/* load BPF program */
if (bpf_object__load(obj)) {
fprintf(stderr, "ERROR: loading BPF object file failed\n");
goto cleanup;
}
map_fd = bpf_object__find_map_fd_by_name(obj, "lat_map");
if (map_fd < 0) {
fprintf(stderr, "ERROR: finding a map in obj file failed\n");
goto cleanup;
}
bpf_object__for_each_program(prog, obj) {
links[j] = bpf_program__attach(prog);
if (libbpf_get_error(links[j])) {
fprintf(stderr, "ERROR: bpf_program__attach failed\n");
links[j] = NULL;
goto cleanup;
}
j++;
}
printf(" heatmap of IO latency\n");
if (text_only)
printf(" %s", sym[num_colors - 1]);
else
printf(" %s %s", color[num_colors - 1], nocolor);
printf(" - many events with this latency\n");
if (text_only)
printf(" %s", sym[0]);
else
printf(" %s %s", color[0], nocolor);
printf(" - few events\n");
for (i = 0; ; i++) {
if (i % 20 == 0)
print_banner();
print_hist(map_fd);
sleep(2);
}
cleanup:
for (j--; j >= 0; j--)
bpf_link__destroy(links[j]);
bpf_object__close(obj);
return 0;
}
|
