1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
|
/* Copyright (c) 2015, Linaro Limited
* All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*
* This program is used to read perf cycle counter using
* perf_event_open/read syscall
*
*/
#define _GNU_SOURCE
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/syscall.h>
#include <linux/perf_event.h>
#include <getopt.h>
#include <math.h>
#include <signal.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>
static int fddev = -1;
static int overflow;
static void sigio_handler(int signo, siginfo_t *info, void *uc)
{
overflow = overflow + 1;
}
static int counter_init(unsigned int counter,long unsigned int sample)
{
static struct perf_event_attr attr;
attr.type = PERF_TYPE_HARDWARE;
static struct sigaction sigio;
if (counter < 0 || counter > PERF_COUNT_HW_MAX)
return -1;
/* setup SIGIO signal handler */
memset(&sigio, 0, sizeof(struct sigaction));
sigio.sa_sigaction = (void *)sigio_handler;
sigio.sa_flags = SA_SIGINFO;
if (sigaction(SIGIO, &sigio, NULL) == -1) {
printf("Error: SIGIO signal handler %s\n",strerror(errno));
}
attr.sample_period = sample;
attr.sample_type = PERF_SAMPLE_IP;
attr.wakeup_events = 1;
attr.config = counter;
fddev = syscall(__NR_perf_event_open, &attr, 0, -1, -1, 0);
if (fddev == -1) {
fprintf(stderr,
"Error opening perf_event_open for counter %llx\n"
, attr.config);
return -1;
}
fcntl(fddev, F_SETFL, O_RDWR|O_NONBLOCK|O_ASYNC);
fcntl(fddev, F_SETSIG, SIGIO);
fcntl(fddev, F_SETOWN, getpid());
return 0;
}
static inline long long cpucycles(void)
{
long long result = 0;
if (read(fddev, &result, sizeof(result)) < sizeof(result))
return 0;
return result;
}
/* loop body to keep things interested. Make sure it gets inlined. */
static inline int
loop(int* __restrict__ a, int* __restrict__ b, int n)
{
unsigned sum = 0;
int i = 0;
for (i = 0; i < n; ++i)
if (a[i] > b[i])
sum += a[i] + 5;
return sum;
}
void print_usage(char *argv)
{
printf("Usage: %s -c perf_hw_counter -n length\n"
"%s - read perf hardware counters from userspace\n\n"
"-c\t perf_hw_counter is enum value of hw counter for platform\n"
"Refer to 'enum perf_hw_id'[file <linux/perf_event.h>] for hw\n"
"counter enum value in range of 0 to PERF_COUNT_HW_MAX\n"
"-n\t Length size array will implement busyloop\n"
"-s\t Sample period [> 1000000 samples]\n"
"e.g.\n"
"\t%s -c 0 -n 64 -s 1000000\n", argv, argv, argv);
}
int main(int ac, char *argv[])
{
long long time_start = 0;
long long time_end = 0;
int option = 0;
int len = -1, cnt = -1;
int *a = NULL;
int *b = NULL;
int i, pre_loop_res, post_loop_res, sum = 0;
unsigned long s_period = 1000000;
#ifdef MAX_DELAY
unsigned long tmp_value = 0;
unsigned long max_value = 0;
#endif
while ((option = getopt(ac, argv, "c:n:s:")) != -1) {
switch (option) {
case 'c':
cnt = atoi(optarg);
break;
case 'n':
len = atoi(optarg);
break;
case 's':
s_period = atoi(optarg);
break;
default:
print_usage(argv[0]);
exit(EXIT_FAILURE);
}
}
if (len == -1 || cnt == -1) {
print_usage(argv[0]);
exit(EXIT_FAILURE);
}
if (counter_init(cnt, s_period) < 0) {
printf("Error: Counter Invalid\n");
print_usage(argv[0]);
exit(EXIT_FAILURE);
}
a = malloc(len*sizeof(*a));
b = malloc(len*sizeof(*b));
ioctl(fddev, PERF_EVENT_IOC_RESET, 0);
ioctl(fddev, PERF_EVENT_IOC_ENABLE, 0);
for (i = 0; i < len; ++i) {
a[i] = i+128;
b[i] = i+64;
}
time_start = time_end = 0;
/* --------------------Critical section-------------- */
time_start = cpucycles();
for (i = 0; i < 1000; i++) {
sum = loop(a, b, len);
#ifndef MAX_DELAY
cpucycles();
#else
tmp_value = cpucycles();
if ( max_value < tmp_value ) {
max_value = tmp_value;
}
#endif
}
time_end = cpucycles();
/* ---------------------------------- */
pre_loop_res = abs(time_end-time_start)/1000;
time_start = time_end = 0;
ioctl(fddev, PERF_EVENT_IOC_RESET, 0);
/* --------------------Critical section-------------- */
time_start = cpucycles();
for (i = 0; i < 1000; i++)
sum = loop(a, b, len);
time_end = cpucycles();
/* ---------------------------------- */
ioctl(fddev, PERF_EVENT_IOC_DISABLE, 0);
post_loop_res = abs(time_end-time_start)/1000;
#ifndef MAX_DELAY
printf("\t%s Counter[%d] avg delay[cpucycles]=%d overflows=%d\n", argv[0], cnt, abs(post_loop_res - pre_loop_res),overflow);
#else
printf("\t%s Counter[%d] max delay[cpucycles]=%ld avg delay[cpucycles]=%d Overflows=%d\n", argv[0], cnt, max_value, abs(post_loop_res - pre_loop_res),overflow);
#endif
free(a);
free(b);
close(fddev);
return 0;
}
|
