You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
53 lines
1.1 KiB
53 lines
1.1 KiB
// Copyright (c) 2016-2017 The Bitcoin Core developers |
|
// Distributed under the MIT software license, see the accompanying |
|
// file COPYING or http://www.opensource.org/licenses/mit-license.php. |
|
|
|
#include <bench/perf.h> |
|
|
|
#if defined(__i386__) || defined(__x86_64__) |
|
|
|
/* These architectures support querying the cycle counter |
|
* from user space, no need for any syscall overhead. |
|
*/ |
|
void perf_init(void) { } |
|
void perf_fini(void) { } |
|
|
|
#elif defined(__linux__) |
|
|
|
#include <unistd.h> |
|
#include <sys/syscall.h> |
|
#include <linux/perf_event.h> |
|
|
|
static int fd = -1; |
|
static struct perf_event_attr attr; |
|
|
|
void perf_init(void) |
|
{ |
|
attr.type = PERF_TYPE_HARDWARE; |
|
attr.config = PERF_COUNT_HW_CPU_CYCLES; |
|
fd = syscall(__NR_perf_event_open, &attr, 0, -1, -1, 0); |
|
} |
|
|
|
void perf_fini(void) |
|
{ |
|
if (fd != -1) { |
|
close(fd); |
|
} |
|
} |
|
|
|
uint64_t perf_cpucycles(void) |
|
{ |
|
uint64_t result = 0; |
|
if (fd == -1 || read(fd, &result, sizeof(result)) < (ssize_t)sizeof(result)) { |
|
return 0; |
|
} |
|
return result; |
|
} |
|
|
|
#else /* Unhandled platform */ |
|
|
|
void perf_init(void) { } |
|
void perf_fini(void) { } |
|
uint64_t perf_cpucycles(void) { return 0; } |
|
|
|
#endif
|
|
|