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
|
/************************************************************************/
/* * The Coq Proof Assistant / The Coq Development Team */
/* v * Copyright INRIA, CNRS and contributors */
/* <O___,, * (see version control and CREDITS file for authors & dates) */
/* \VV/ **************************************************************/
/* // * This file is distributed under the terms of the */
/* * GNU Lesser General Public License Version 2.1 */
/* * (see LICENSE file for the text of the license) */
/************************************************************************/
#include <linux/perf_event.h>
#include <sys/syscall.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <caml/mlvalues.h>
#include <caml/memory.h>
#include <caml/alloc.h>
#include <caml/fail.h>
static int perf_event_open(struct perf_event_attr *hw_event, pid_t pid,
int cpu, int group_fd, unsigned long flags) {
return syscall(SYS_perf_event_open, hw_event, pid, cpu, group_fd, flags);
}
#define NOT_INITIALIZED (-2)
int fd = NOT_INITIALIZED;
CAMLprim value CAML_init(value unit) {
CAMLparam1(unit);
if (fd != NOT_INITIALIZED) {
caml_failwith("counter already initialized");
}
struct perf_event_attr pe;
memset(&pe, 0, sizeof(pe));
pe.type = PERF_TYPE_HARDWARE;
pe.size = sizeof(pe);
pe.config = PERF_COUNT_HW_INSTRUCTIONS;
pe.disabled = 1;
pe.exclude_kernel = 1;
pe.exclude_hv = 1;
fd = perf_event_open(&pe, 0, -1, -1, 0);
if (fd == -1) {
fd = NOT_INITIALIZED;
caml_failwith("initialisation failure");
}
if (ioctl(fd, PERF_EVENT_IOC_RESET , 0) == -1) {
close(fd);
fd = NOT_INITIALIZED;
caml_failwith("could not initially reset counter");
}
if (ioctl(fd, PERF_EVENT_IOC_ENABLE, 0) == -1) {
close(fd);
fd = NOT_INITIALIZED;
caml_failwith("could not initailly enable counter");
}
CAMLreturn(Val_unit);
}
CAMLprim value CAML_drop(value unit) {
CAMLparam1(unit);
if (fd == NOT_INITIALIZED) {
caml_failwith("counter not initialized");
}
close(fd);
fd = NOT_INITIALIZED;
CAMLreturn(Val_unit);
}
CAMLprim value CAML_peek(value unit) {
CAMLparam1(unit);
if (fd == NOT_INITIALIZED) caml_failwith("counter not initialized");
if (ioctl(fd, PERF_EVENT_IOC_DISABLE, 0) == -1) {
caml_failwith("could not disable counter");
}
int64_t count = 0;
size_t n = read(fd, &count, sizeof(count));
if (n != sizeof(count)) {
caml_failwith("could not retrieve counter");
}
value ret = caml_copy_int64(count);
if (ioctl(fd, PERF_EVENT_IOC_ENABLE, 0) == -1) {
caml_failwith("could not enable counter");
}
CAMLreturn(ret);
}
|
