1
2
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 <linux/bpf.h>
11#include <sys/resource.h>
12
13#include <bpf/bpf.h>
14#include "bpf_load.h"
15#include "bpf_util.h"
16
17#define SLOTS 100
18
19static void clear_stats(int fd)
20{
21 unsigned int nr_cpus = bpf_num_possible_cpus();
22 __u64 values[nr_cpus];
23 __u32 key;
24
25 memset(values, 0, sizeof(values));
26 for (key = 0; key < SLOTS; key++)
27 bpf_map_update_elem(fd, &key, values, BPF_ANY);
28}
29
30const char *color[] = {
31 "\033[48;5;255m",
32 "\033[48;5;252m",
33 "\033[48;5;250m",
34 "\033[48;5;248m",
35 "\033[48;5;246m",
36 "\033[48;5;244m",
37 "\033[48;5;242m",
38 "\033[48;5;240m",
39 "\033[48;5;238m",
40 "\033[48;5;236m",
41 "\033[48;5;234m",
42 "\033[48;5;232m",
43};
44const int num_colors = ARRAY_SIZE(color);
45
46const char nocolor[] = "\033[00m";
47
48const char *sym[] = {
49 " ",
50 " ",
51 ".",
52 ".",
53 "*",
54 "*",
55 "o",
56 "o",
57 "O",
58 "O",
59 "#",
60 "#",
61};
62
63bool full_range = false;
64bool text_only = false;
65
66static void print_banner(void)
67{
68 if (full_range)
69 printf("|1ns |10ns |100ns |1us |10us |100us"
70 " |1ms |10ms |100ms |1s |10s\n");
71 else
72 printf("|1us |10us |100us |1ms |10ms "
73 "|100ms |1s |10s\n");
74}
75
76static void print_hist(int fd)
77{
78 unsigned int nr_cpus = bpf_num_possible_cpus();
79 __u64 total_events = 0;
80 long values[nr_cpus];
81 __u64 max_cnt = 0;
82 __u64 cnt[SLOTS];
83 __u64 value;
84 __u32 key;
85 int i;
86
87 for (key = 0; key < SLOTS; key++) {
88 bpf_map_lookup_elem(fd, &key, values);
89 value = 0;
90 for (i = 0; i < nr_cpus; i++)
91 value += values[i];
92 cnt[key] = value;
93 total_events += value;
94 if (value > max_cnt)
95 max_cnt = value;
96 }
97 clear_stats(fd);
98 for (key = full_range ? 0 : 29; key < SLOTS; key++) {
99 int c = num_colors * cnt[key] / (max_cnt + 1);
100
101 if (text_only)
102 printf("%s", sym[c]);
103 else
104 printf("%s %s", color[c], nocolor);
105 }
106 printf(" # %lld\n", total_events);
107}
108
109int main(int ac, char **argv)
110{
111 struct rlimit r = {1024*1024, RLIM_INFINITY};
112 char filename[256];
113 int i;
114
115 snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
116
117 if (setrlimit(RLIMIT_MEMLOCK, &r)) {
118 perror("setrlimit(RLIMIT_MEMLOCK)");
119 return 1;
120 }
121
122 if (load_bpf_file(filename)) {
123 printf("%s", bpf_log_buf);
124 return 1;
125 }
126
127 for (i = 1; i < ac; i++) {
128 if (strcmp(argv[i], "-a") == 0) {
129 full_range = true;
130 } else if (strcmp(argv[i], "-t") == 0) {
131 text_only = true;
132 } else if (strcmp(argv[i], "-h") == 0) {
133 printf("Usage:\n"
134 " -a display wider latency range\n"
135 " -t text only\n");
136 return 1;
137 }
138 }
139
140 printf(" heatmap of IO latency\n");
141 if (text_only)
142 printf(" %s", sym[num_colors - 1]);
143 else
144 printf(" %s %s", color[num_colors - 1], nocolor);
145 printf(" - many events with this latency\n");
146
147 if (text_only)
148 printf(" %s", sym[0]);
149 else
150 printf(" %s %s", color[0], nocolor);
151 printf(" - few events\n");
152
153 for (i = 0; ; i++) {
154 if (i % 20 == 0)
155 print_banner();
156 print_hist(map_fd[1]);
157 sleep(2);
158 }
159
160 return 0;
161}
162
