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lavu/timer.h: add Linux Perf API support

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Refer to "checkasm: use perf API on Linux ARM*" commit for the
rationale.

The implementation is somehow duplicated with checkasm, but so is the
current usage of AV_READ_TIME(). Until these implementations and
heuristics are made consistent, I don't see a way of sharing that code.

Note: when using libavutil/timer.h, it is now important to include
before any other include due to the _GNU_SOURCE requirement.
This commit is contained in:
Clément Bœsch 2017-09-02 19:25:10 +02:00 committed by Clément Bœsch
parent e0b9b3e60e
commit f61379cbd4
1 changed files with 43 additions and 3 deletions
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46
libavutil/timer.h
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@ -26,12 +26,22 @@
#ifndef AVUTIL_TIMER_H #ifndef AVUTIL_TIMER_H
#define AVUTIL_TIMER_H #define AVUTIL_TIMER_H
#include "config.h"
#if CONFIG_LINUX_PERF
# ifndef _GNU_SOURCE
# define _GNU_SOURCE
# endif
# include <unistd.h> // read(3)
# include <sys/ioctl.h>
# include <asm/unistd.h>
# include <linux/perf_event.h>
#endif
#include <stdlib.h> #include <stdlib.h>
#include <stdint.h> #include <stdint.h>
#include <inttypes.h> #include <inttypes.h>
#include "config.h"
#if HAVE_MACH_MACH_TIME_H #if HAVE_MACH_MACH_TIME_H
#include <mach/mach_time.h> #include <mach/mach_time.h>
#endif #endif
@ -85,7 +95,37 @@
} \ } \
} }
#ifdef AV_READ_TIME #if CONFIG_LINUX_PERF
#define START_TIMER \
static int linux_perf_fd; \
uint64_t tperf; \
if (!linux_perf_fd) { \
struct perf_event_attr attr = { \
.type = PERF_TYPE_HARDWARE, \
.size = sizeof(struct perf_event_attr), \
.config = PERF_COUNT_HW_CPU_CYCLES, \
.disabled = 1, \
.exclude_kernel = 1, \
.exclude_hv = 1, \
}; \
linux_perf_fd = syscall(__NR_perf_event_open, &attr, \
0, -1, -1, 0); \
} \
if (linux_perf_fd == -1) { \
av_log(NULL, AV_LOG_ERROR, "perf_event_open failed: %s\n", \
av_err2str(AVERROR(errno))); \
} else { \
ioctl(linux_perf_fd, PERF_EVENT_IOC_RESET, 0); \
ioctl(linux_perf_fd, PERF_EVENT_IOC_ENABLE, 0); \
}
#define STOP_TIMER(id) \
ioctl(linux_perf_fd, PERF_EVENT_IOC_DISABLE, 0); \
read(linux_perf_fd, &tperf, sizeof(tperf)); \
TIMER_REPORT(id, tperf)
#elif defined(AV_READ_TIME)
#define START_TIMER \ #define START_TIMER \
uint64_t tend; \ uint64_t tend; \
uint64_t tstart = AV_READ_TIME(); \ uint64_t tstart = AV_READ_TIME(); \