[FFmpeg-cvslog] lavu: add support for atomic operations.
Ronald S. Bultje
git at videolan.org
Fri Mar 8 15:55:24 CET 2013
ffmpeg | branch: master | Ronald S. Bultje <rsbultje at gmail.com> | Sun Dec 2 14:34:50 2012 -0800| [65f1d45dcc71186ede72fff950996099d23359bd] | committer: Anton Khirnov
lavu: add support for atomic operations.
These could be used for reference counting, or for keeping track of
decoding progress in references in multithreaded decoders.
Support is provided by gcc/msvc/suncc intrinsics, with a fallback using
pthread mutexes.
Signed-off-by: Anton Khirnov <anton at khirnov.net>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=65f1d45dcc71186ede72fff950996099d23359bd
---
configure | 6 +++
libavutil/Makefile | 2 +
libavutil/atomic.c | 123 ++++++++++++++++++++++++++++++++++++++++++++++
libavutil/atomic.h | 74 ++++++++++++++++++++++++++++
libavutil/atomic_gcc.h | 48 ++++++++++++++++++
libavutil/atomic_suncc.h | 51 +++++++++++++++++++
libavutil/atomic_win32.h | 50 +++++++++++++++++++
tests/fate/libavutil.mak | 5 ++
8 files changed, 359 insertions(+)
diff --git a/configure b/configure
index d9708e8..a4b12c6 100755
--- a/configure
+++ b/configure
@@ -1285,9 +1285,11 @@ HAVE_LIST="
loongson
machine_ioctl_bt848_h
machine_ioctl_meteor_h
+ machine_rw_barrier
malloc_h
MapViewOfFile
memalign
+ MemoryBarrier
mkstemp
mm_empty
mmap
@@ -1322,6 +1324,7 @@ HAVE_LIST="
struct_v4l2_frmivalenum_discrete
symver_asm_label
symver_gnu_asm
+ sync_synchronize
sysconf
sysctl
sys_mman_h
@@ -3453,6 +3456,9 @@ check_func strerror_r
check_func strptime
check_func strtok_r
check_func sched_getaffinity
+check_builtin sync_synchronize "" "__sync_synchronize()"
+check_builtin machine_rw_barrier mbarrier.h "__machine_rw_barrier()"
+check_builtin MemoryBarrier windows.h "MemoryBarrier()"
check_func sysconf
check_func sysctl
check_func usleep
diff --git a/libavutil/Makefile b/libavutil/Makefile
index 465b2fc..4406b13 100644
--- a/libavutil/Makefile
+++ b/libavutil/Makefile
@@ -54,6 +54,7 @@ BUILT_HEADERS = avconfig.h
OBJS = adler32.o \
aes.o \
+ atomic.o \
audio_fifo.o \
avstring.o \
base64.o \
@@ -100,6 +101,7 @@ SKIPHEADERS = old_pix_fmts.h
TESTPROGS = adler32 \
aes \
+ atomic \
avstring \
base64 \
blowfish \
diff --git a/libavutil/atomic.c b/libavutil/atomic.c
new file mode 100644
index 0000000..8fa2532
--- /dev/null
+++ b/libavutil/atomic.c
@@ -0,0 +1,123 @@
+/*
+ * Copyright (c) 2012 Ronald S. Bultje <rsbultje at gmail.com>
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "atomic.h"
+
+#if !HAVE_MEMORYBARRIER && !HAVE_SYNC_SYNCHRONIZE && !HAVE_MACHINE_RW_BARRIER
+
+#if HAVE_PTHREADS
+
+#include <pthread.h>
+
+static pthread_mutex_t atomic_lock = PTHREAD_MUTEX_INITIALIZER;
+
+int avpriv_atomic_int_get(volatile int *ptr)
+{
+ int res;
+
+ pthread_mutex_lock(&atomic_lock);
+ res = *ptr;
+ pthread_mutex_unlock(&atomic_lock);
+
+ return res;
+}
+
+void avpriv_atomic_int_set(volatile int *ptr, int val)
+{
+ pthread_mutex_lock(&atomic_lock);
+ *ptr = val;
+ pthread_mutex_unlock(&atomic_lock);
+}
+
+int avpriv_atomic_int_add_and_fetch(volatile int *ptr, int inc)
+{
+ int res;
+
+ pthread_mutex_lock(&atomic_lock);
+ *ptr += inc;
+ res = *ptr;
+ pthread_mutex_unlock(&atomic_lock);
+
+ return res;
+}
+
+void *avpriv_atomic_ptr_cas(void * volatile *ptr, void *oldval, void *newval)
+{
+ void *ret;
+ pthread_mutex_lock(&atomic_lock);
+ ret = *ptr;
+ if (*ptr == oldval)
+ *ptr = newval;
+ pthread_mutex_unlock(&atomic_lock);
+ return ret;
+}
+
+#elif !HAVE_THREADS
+
+int avpriv_atomic_int_get(volatile int *ptr)
+{
+ return *ptr;
+}
+
+void avpriv_atomic_int_set(volatile int *ptr, int val)
+{
+ *ptr = val;
+}
+
+int avpriv_atomic_int_add_and_fetch(volatile int *ptr, int inc)
+{
+ *ptr += inc;
+ return *ptr;
+}
+
+void *avpriv_atomic_ptr_cas(void * volatile *ptr, void *oldval, void *newval)
+{
+ if (*ptr == oldval) {
+ *ptr = newval;
+ return oldval;
+ }
+ return *ptr;
+}
+
+#else
+
+#error "Threading is enabled, but there is no implementation of atomic operations available"
+
+#endif /* HAVE_PTHREADS */
+
+#endif /* !HAVE_MEMORYBARRIER && !HAVE_SYNC_SYNCHRONIZE && !HAVE_MACHINE_RW_BARRIER */
+
+#ifdef TEST
+#include <assert.h>
+
+int main(void)
+{
+ volatile int val = 1;
+ int res;
+
+ res = avpriv_atomic_int_add_and_fetch(&val, 1);
+ assert(res == 2);
+ avpriv_atomic_int_set(&val, 3);
+ res = avpriv_atomic_int_get(&val);
+ assert(res == 3);
+
+ return 0;
+}
+#endif
diff --git a/libavutil/atomic.h b/libavutil/atomic.h
new file mode 100644
index 0000000..dad93bd
--- /dev/null
+++ b/libavutil/atomic.h
@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2012 Ronald S. Bultje <rsbultje at gmail.com>
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVUTIL_ATOMIC_H
+#define AVUTIL_ATOMIC_H
+
+#include "config.h"
+
+#if HAVE_MEMORYBARRIER
+#include "atomic_win32.h"
+#elif HAVE_SYNC_SYNCHRONIZE
+#include "atomic_gcc.h"
+#elif HAVE_MACHINE_RW_BARRIER
+#include "atomic_suncc.h"
+#else
+
+/**
+ * Load the current value stored in an atomic integer.
+ *
+ * @param ptr atomic integer
+ * @return the current value of the atomic integer
+ * @note This acts as a memory barrier.
+ */
+int avpriv_atomic_int_get(volatile int *ptr);
+
+/**
+ * Store a new value in an atomic integer.
+ *
+ * @param ptr atomic integer
+ * @param val the value to store in the atomic integer
+ * @note This acts as a memory barrier.
+ */
+void avpriv_atomic_int_set(volatile int *ptr, int val);
+
+/**
+ * Add a value to an atomic integer.
+ *
+ * @param ptr atomic integer
+ * @param inc the value to add to the atomic integer (may be negative)
+ * @return the new value of the atomic integer.
+ * @note This does NOT act as a memory barrier. This is primarily
+ * intended for reference counting.
+ */
+int avpriv_atomic_int_add_and_fetch(volatile int *ptr, int inc);
+
+/**
+ * Atomic pointer compare and swap.
+ *
+ * @param ptr pointer to the pointer to operate on
+ * @param oldval do the swap if the current value of *ptr equals to oldval
+ * @param newval value to replace *ptr with
+ * @return the value of *ptr before comparison
+ */
+void *avpriv_atomic_ptr_cas(void * volatile *ptr, void *oldval, void *newval);
+
+#endif /* HAVE_MEMORYBARRIER */
+#endif /* AVUTIL_ATOMIC_H */
diff --git a/libavutil/atomic_gcc.h b/libavutil/atomic_gcc.h
new file mode 100644
index 0000000..e2f3fe1
--- /dev/null
+++ b/libavutil/atomic_gcc.h
@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2012 Ronald S. Bultje <rsbultje at gmail.com>
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "atomic.h"
+
+#define avpriv_atomic_int_get atomic_int_get_gcc
+static inline int atomic_int_get_gcc(volatile int *ptr)
+{
+ __sync_synchronize();
+ return *ptr;
+}
+
+#define avpriv_atomic_int_set atomic_int_set_gcc
+static inline void atomic_int_set_gcc(volatile int *ptr, int val)
+{
+ *ptr = val;
+ __sync_synchronize();
+}
+
+#define avpriv_atomic_int_add_and_fetch atomic_int_add_and_fetch_gcc
+static inline int atomic_int_add_and_fetch_gcc(volatile int *ptr, int inc)
+{
+ return __sync_add_and_fetch(ptr, inc);
+}
+
+#define avpriv_atomic_ptr_cas atomic_ptr_cas_gcc
+static inline void *atomic_ptr_cas_gcc(void * volatile *ptr,
+ void *oldval, void *newval)
+{
+ return __sync_val_compare_and_swap(ptr, oldval, newval);
+}
diff --git a/libavutil/atomic_suncc.h b/libavutil/atomic_suncc.h
new file mode 100644
index 0000000..85373f5
--- /dev/null
+++ b/libavutil/atomic_suncc.h
@@ -0,0 +1,51 @@
+/*
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <atomic.h>
+#include <mbarrier.h>
+
+#include "atomic.h"
+
+#define avpriv_atomic_int_get atomic_int_get_suncc
+static inline int atomic_int_get_suncc(volatile int *ptr)
+{
+ __machine_rw_barrier();
+ return *ptr;
+}
+
+#define avpriv_atomic_int_set atomic_int_set_suncc
+static inline void atomic_int_set_suncc(volatile int *ptr, int val)
+{
+ *ptr = val;
+ __machine_rw_barrier();
+}
+
+#define avpriv_atomic_int_add_and_fetch atomic_int_add_and_fetch_suncc
+static inline int atomic_int_add_and_fetch_suncc(volatile int *ptr, int inc)
+{
+ return atomic_add_int_nv(ptr, inc);
+}
+
+#define avpriv_atomic_ptr_cas atomic_ptr_cas_suncc
+static inline void *atomic_ptr_cas_suncc(void * volatile *ptr,
+ void *oldval, void *newval)
+{
+ return atomic_cas_ptr(ptr, oldval, newval);
+}
+
diff --git a/libavutil/atomic_win32.h b/libavutil/atomic_win32.h
new file mode 100644
index 0000000..6ae61f6
--- /dev/null
+++ b/libavutil/atomic_win32.h
@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2012 Ronald S. Bultje <rsbultje at gmail.com>
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <windows.h>
+
+#include "atomic.h"
+
+#define avpriv_atomic_int_get atomic_int_get_win32
+static inline int atomic_int_get_win32(volatile int *ptr)
+{
+ MemoryBarrier();
+ return *ptr;
+}
+
+#define avpriv_atomic_int_set atomic_int_set_win32
+static inline void atomic_int_set_win32(volatile int *ptr, int val)
+{
+ *ptr = val;
+ MemoryBarrier();
+}
+
+#define avpriv_atomic_int_add_and_fetch atomic_int_add_and_fetch_win32
+static inline int atomic_int_add_and_fetch_win32(volatile int *ptr, int inc)
+{
+ return inc + InterlockedExchangeAdd(ptr, inc);
+}
+
+#define avpriv_atomic_ptr_cas atomic_ptr_cas_win32
+static inline void *atomic_ptr_cas_win32(void * volatile *ptr,
+ void *oldval, void *newval)
+{
+ return InterlockedCompareExchangePointer(ptr, newval, oldval);
+}
diff --git a/tests/fate/libavutil.mak b/tests/fate/libavutil.mak
index 5befcce..3777625 100644
--- a/tests/fate/libavutil.mak
+++ b/tests/fate/libavutil.mak
@@ -8,6 +8,11 @@ fate-aes: libavutil/aes-test$(EXESUF)
fate-aes: CMD = run libavutil/aes-test
fate-aes: REF = /dev/null
+FATE_LIBAVUTIL += fate-atomic
+fate-atomic: libavutil/atomic-test$(EXESUF)
+fate-atomic: CMD = run libavutil/atomic-test
+fate-atomic: REF = /dev/null
+
FATE_LIBAVUTIL += fate-avstring
fate-avstring: libavutil/avstring-test$(EXESUF)
fate-avstring: CMD = run libavutil/avstring-test
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