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- // SPDX-License-Identifier: GPL-2.0-only
- /* Copyright (c) 2013-2015 PLUMgrid, http://plumgrid.com
- * Copyright (c) 2015 BMW Car IT GmbH
- */
- #include <stdio.h>
- #include <unistd.h>
- #include <stdlib.h>
- #include <signal.h>
- #include <bpf/libbpf.h>
- #include <bpf/bpf.h>
- #define MAX_ENTRIES 20
- #define MAX_CPU 4
- #define MAX_STARS 40
- struct cpu_hist {
- long data[MAX_ENTRIES];
- long max;
- };
- static struct cpu_hist cpu_hist[MAX_CPU];
- static void stars(char *str, long val, long max, int width)
- {
- int i;
- for (i = 0; i < (width * val / max) - 1 && i < width - 1; i++)
- str[i] = '*';
- if (val > max)
- str[i - 1] = '+';
- str[i] = '\0';
- }
- static void print_hist(void)
- {
- char starstr[MAX_STARS];
- struct cpu_hist *hist;
- int i, j;
- /* clear screen */
- printf("\033[2J");
- for (j = 0; j < MAX_CPU; j++) {
- hist = &cpu_hist[j];
- /* ignore CPUs without data (maybe offline?) */
- if (hist->max == 0)
- continue;
- printf("CPU %d\n", j);
- printf(" latency : count distribution\n");
- for (i = 1; i <= MAX_ENTRIES; i++) {
- stars(starstr, hist->data[i - 1], hist->max, MAX_STARS);
- printf("%8ld -> %-8ld : %-8ld |%-*s|\n",
- (1l << i) >> 1, (1l << i) - 1,
- hist->data[i - 1], MAX_STARS, starstr);
- }
- }
- }
- static void get_data(int fd)
- {
- long key, value;
- int c, i;
- for (i = 0; i < MAX_CPU; i++)
- cpu_hist[i].max = 0;
- for (c = 0; c < MAX_CPU; c++) {
- for (i = 0; i < MAX_ENTRIES; i++) {
- key = c * MAX_ENTRIES + i;
- bpf_map_lookup_elem(fd, &key, &value);
- cpu_hist[c].data[i] = value;
- if (value > cpu_hist[c].max)
- cpu_hist[c].max = value;
- }
- }
- }
- int main(int argc, char **argv)
- {
- struct bpf_link *links[2];
- struct bpf_program *prog;
- struct bpf_object *obj;
- char filename[256];
- int map_fd, i = 0;
- 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, "my_lat");
- 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[i] = bpf_program__attach(prog);
- if (libbpf_get_error(links[i])) {
- fprintf(stderr, "ERROR: bpf_program__attach failed\n");
- links[i] = NULL;
- goto cleanup;
- }
- i++;
- }
- while (1) {
- get_data(map_fd);
- print_hist();
- sleep(5);
- }
- cleanup:
- for (i--; i >= 0; i--)
- bpf_link__destroy(links[i]);
- bpf_object__close(obj);
- return 0;
- }
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