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  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#include <sys/resource.h>
 15
 16#include "libbpf.h"
 17#include "bpf_load.h"
 18#include "bpf_util.h"
 19
 20#define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x)))
 21
 22#define SLOTS 100
 23
 24static void clear_stats(int fd)
 25{
 26	unsigned int nr_cpus = bpf_num_possible_cpus();
 27	__u64 values[nr_cpus];
 28	__u32 key;
 29
 30	memset(values, 0, sizeof(values));
 31	for (key = 0; key < SLOTS; key++)
 32		bpf_map_update_elem(fd, &key, values, BPF_ANY);
 33}
 34
 35const char *color[] = {
 36	"\033[48;5;255m",
 37	"\033[48;5;252m",
 38	"\033[48;5;250m",
 39	"\033[48;5;248m",
 40	"\033[48;5;246m",
 41	"\033[48;5;244m",
 42	"\033[48;5;242m",
 43	"\033[48;5;240m",
 44	"\033[48;5;238m",
 45	"\033[48;5;236m",
 46	"\033[48;5;234m",
 47	"\033[48;5;232m",
 48};
 49const int num_colors = ARRAY_SIZE(color);
 50
 51const char nocolor[] = "\033[00m";
 52
 53const char *sym[] = {
 54	" ",
 55	" ",
 56	".",
 57	".",
 58	"*",
 59	"*",
 60	"o",
 61	"o",
 62	"O",
 63	"O",
 64	"#",
 65	"#",
 66};
 67
 68bool full_range = false;
 69bool text_only = false;
 70
 71static void print_banner(void)
 72{
 73	if (full_range)
 74		printf("|1ns     |10ns     |100ns    |1us      |10us     |100us"
 75		       "    |1ms      |10ms     |100ms    |1s       |10s\n");
 76	else
 77		printf("|1us      |10us     |100us    |1ms      |10ms     "
 78		       "|100ms    |1s       |10s\n");
 79}
 80
 81static void print_hist(int fd)
 82{
 83	unsigned int nr_cpus = bpf_num_possible_cpus();
 84	__u64 total_events = 0;
 85	long values[nr_cpus];
 86	__u64 max_cnt = 0;
 87	__u64 cnt[SLOTS];
 88	__u64 value;
 89	__u32 key;
 90	int i;
 91
 92	for (key = 0; key < SLOTS; key++) {
 93		bpf_map_lookup_elem(fd, &key, values);
 94		value = 0;
 95		for (i = 0; i < nr_cpus; i++)
 96			value += values[i];
 97		cnt[key] = value;
 98		total_events += value;
 99		if (value > max_cnt)
100			max_cnt = value;
101	}
102	clear_stats(fd);
103	for (key = full_range ? 0 : 29; key < SLOTS; key++) {
104		int c = num_colors * cnt[key] / (max_cnt + 1);
105
106		if (text_only)
107			printf("%s", sym[c]);
108		else
109			printf("%s %s", color[c], nocolor);
110	}
111	printf(" # %lld\n", total_events);
112}
113
114int main(int ac, char **argv)
115{
116	struct rlimit r = {1024*1024, RLIM_INFINITY};
117	char filename[256];
118	int i;
119
120	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
121
122	if (setrlimit(RLIMIT_MEMLOCK, &r)) {
123		perror("setrlimit(RLIMIT_MEMLOCK)");
124		return 1;
125	}
126
127	if (load_bpf_file(filename)) {
128		printf("%s", bpf_log_buf);
129		return 1;
130	}
131
132	for (i = 1; i < ac; i++) {
133		if (strcmp(argv[i], "-a") == 0) {
134			full_range = true;
135		} else if (strcmp(argv[i], "-t") == 0) {
136			text_only = true;
137		} else if (strcmp(argv[i], "-h") == 0) {
138			printf("Usage:\n"
139			       "  -a display wider latency range\n"
140			       "  -t text only\n");
141			return 1;
142		}
143	}
144
145	printf("  heatmap of IO latency\n");
146	if (text_only)
147		printf("  %s", sym[num_colors - 1]);
148	else
149		printf("  %s %s", color[num_colors - 1], nocolor);
150	printf(" - many events with this latency\n");
151
152	if (text_only)
153		printf("  %s", sym[0]);
154	else
155		printf("  %s %s", color[0], nocolor);
156	printf(" - few events\n");
157
158	for (i = 0; ; i++) {
159		if (i % 20 == 0)
160			print_banner();
161		print_hist(map_fd[1]);
162		sleep(2);
163	}
164
165	return 0;
166}