• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
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 bpf_link *links[2];
111 	struct bpf_program *prog;
112 	struct bpf_object *obj;
113 	char filename[256];
114 	int map_fd, i, j = 0;
115 
116 	for (i = 1; i < ac; i++) {
117 		if (strcmp(argv[i], "-a") == 0) {
118 			full_range = true;
119 		} else if (strcmp(argv[i], "-t") == 0) {
120 			text_only = true;
121 		} else if (strcmp(argv[i], "-h") == 0) {
122 			printf("Usage:\n"
123 			       "  -a display wider latency range\n"
124 			       "  -t text only\n");
125 			return 1;
126 		}
127 	}
128 
129 	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
130 	obj = bpf_object__open_file(filename, NULL);
131 	if (libbpf_get_error(obj)) {
132 		fprintf(stderr, "ERROR: opening BPF object file failed\n");
133 		return 0;
134 	}
135 
136 	/* load BPF program */
137 	if (bpf_object__load(obj)) {
138 		fprintf(stderr, "ERROR: loading BPF object file failed\n");
139 		goto cleanup;
140 	}
141 
142 	map_fd = bpf_object__find_map_fd_by_name(obj, "lat_map");
143 	if (map_fd < 0) {
144 		fprintf(stderr, "ERROR: finding a map in obj file failed\n");
145 		goto cleanup;
146 	}
147 
148 	bpf_object__for_each_program(prog, obj) {
149 		links[j] = bpf_program__attach(prog);
150 		if (libbpf_get_error(links[j])) {
151 			fprintf(stderr, "ERROR: bpf_program__attach failed\n");
152 			links[j] = NULL;
153 			goto cleanup;
154 		}
155 		j++;
156 	}
157 
158 	printf("  heatmap of IO latency\n");
159 	if (text_only)
160 		printf("  %s", sym[num_colors - 1]);
161 	else
162 		printf("  %s %s", color[num_colors - 1], nocolor);
163 	printf(" - many events with this latency\n");
164 
165 	if (text_only)
166 		printf("  %s", sym[0]);
167 	else
168 		printf("  %s %s", color[0], nocolor);
169 	printf(" - few events\n");
170 
171 	for (i = 0; ; i++) {
172 		if (i % 20 == 0)
173 			print_banner();
174 		print_hist(map_fd);
175 		sleep(2);
176 	}
177 
178 cleanup:
179 	for (j--; j >= 0; j--)
180 		bpf_link__destroy(links[j]);
181 
182 	bpf_object__close(obj);
183 	return 0;
184 }
185