[FFmpeg-cvslog] lavu/timer.h: add Linux Perf API support
Clément Bœsch
git at videolan.org
Fri Sep 8 19:52:45 EEST 2017
ffmpeg | branch: master | Clément Bœsch <cboesch at gopro.com> | Sat Sep 2 19:25:10 2017 +0200| [f61379cbd45a91b26c7a1ddd3f16417466c435cd] | committer: Clément Bœsch
lavu/timer.h: add Linux Perf API support
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.
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=f61379cbd45a91b26c7a1ddd3f16417466c435cd
---
libavutil/timer.h | 46 +++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 43 insertions(+), 3 deletions(-)
diff --git a/libavutil/timer.h b/libavutil/timer.h
index da0761b607..f7ab455df2 100644
--- a/libavutil/timer.h
+++ b/libavutil/timer.h
@@ -26,12 +26,22 @@
#ifndef 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 <stdint.h>
#include <inttypes.h>
-#include "config.h"
-
#if HAVE_MACH_MACH_TIME_H
#include <mach/mach_time.h>
#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 \
uint64_t tend; \
uint64_t tstart = AV_READ_TIME(); \
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