1/* Copyright (c) 2013-2015 PLUMgrid, http://plumgrid.com
  2 *
  3 * This program is free software; you can redistribute it and/or
  4 * modify it under the terms of version 2 of the GNU General Public
  5 * License as published by the Free Software Foundation.
  6 */
  7#include <stdio.h>
  8#include <stdlib.h>
  9#include <signal.h>
 10#include <unistd.h>
 11#include <stdbool.h>
 12#include <string.h>
 13#include <linux/bpf.h>
 14
 15#include "libbpf.h"
 16#include "bpf_load.h"
 17#include "bpf_util.h"
 18
 19#define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x)))
 20
 21#define SLOTS 100
 22
 23static void clear_stats(int fd)
 24{
 25	unsigned int nr_cpus = bpf_num_possible_cpus();
 26	__u64 values[nr_cpus];
 27	__u32 key;
 28
 29	memset(values, 0, sizeof(values));
 30	for (key = 0; key < SLOTS; key++)
 31		bpf_map_update_elem(fd, &key, values, BPF_ANY);
 32}
 33
 34const char *color[] = {
 35	"\033[48;5;255m",
 36	"\033[48;5;252m",
 37	"\033[48;5;250m",
 38	"\033[48;5;248m",
 39	"\033[48;5;246m",
 40	"\033[48;5;244m",
 41	"\033[48;5;242m",
 42	"\033[48;5;240m",
 43	"\033[48;5;238m",
 44	"\033[48;5;236m",
 45	"\033[48;5;234m",
 46	"\033[48;5;232m",
 47};
 48const int num_colors = ARRAY_SIZE(color);
 49
 50const char nocolor[] = "\033[00m";
 51
 52const char *sym[] = {
 53	" ",
 54	" ",
 55	".",
 56	".",
 57	"*",
 58	"*",
 59	"o",
 60	"o",
 61	"O",
 62	"O",
 63	"#",
 64	"#",
 65};
 66
 67bool full_range = false;
 68bool text_only = false;
 69
 70static void print_banner(void)
 71{
 72	if (full_range)
 73		printf("|1ns     |10ns     |100ns    |1us      |10us     |100us"
 74		       "    |1ms      |10ms     |100ms    |1s       |10s\n");
 75	else
 76		printf("|1us      |10us     |100us    |1ms      |10ms     "
 77		       "|100ms    |1s       |10s\n");
 78}
 79
 80static void print_hist(int fd)
 81{
 82	unsigned int nr_cpus = bpf_num_possible_cpus();
 83	__u64 total_events = 0;
 84	long values[nr_cpus];
 85	__u64 max_cnt = 0;
 86	__u64 cnt[SLOTS];
 87	__u64 value;
 88	__u32 key;
 89	int i;
 90
 91	for (key = 0; key < SLOTS; key++) {
 92		bpf_map_lookup_elem(fd, &key, values);
 93		value = 0;
 94		for (i = 0; i < nr_cpus; i++)
 95			value += values[i];
 96		cnt[key] = value;
 97		total_events += value;
 98		if (value > max_cnt)
 99			max_cnt = value;
100	}
101	clear_stats(fd);
102	for (key = full_range ? 0 : 29; key < SLOTS; key++) {
103		int c = num_colors * cnt[key] / (max_cnt + 1);
104
105		if (text_only)
106			printf("%s", sym[c]);
107		else
108			printf("%s %s", color[c], nocolor);
109	}
110	printf(" # %lld\n", total_events);
111}
112
113int main(int ac, char **argv)
114{
115	char filename[256];
116	int i;
117
118	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
119
120	if (load_bpf_file(filename)) {
121		printf("%s", bpf_log_buf);
122		return 1;
123	}
124
125	for (i = 1; i < ac; i++) {
126		if (strcmp(argv[i], "-a") == 0) {
127			full_range = true;
128		} else if (strcmp(argv[i], "-t") == 0) {
129			text_only = true;
130		} else if (strcmp(argv[i], "-h") == 0) {
131			printf("Usage:\n"
132			       "  -a display wider latency range\n"
133			       "  -t text only\n");
134			return 1;
135		}
136	}
137
138	printf("  heatmap of IO latency\n");
139	if (text_only)
140		printf("  %s", sym[num_colors - 1]);
141	else
142		printf("  %s %s", color[num_colors - 1], nocolor);
143	printf(" - many events with this latency\n");
144
145	if (text_only)
146		printf("  %s", sym[0]);
147	else
148		printf("  %s %s", color[0], nocolor);
149	printf(" - few events\n");
150
151	for (i = 0; ; i++) {
152		if (i % 20 == 0)
153			print_banner();
154		print_hist(map_fd[1]);
155		sleep(2);
156	}
157
158	return 0;
159}