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ringbuffer: use gcc atomic operations

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Remove barrier, use GCC atomic operations for ringbuffer
This commit is contained in:
Wim Taymans 2017-04-24 13:18:57 +02:00
parent 02d4dc0efd
commit baada0a330
7 changed files with 32 additions and 92 deletions
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51
spa/include/spa/barrier.h
View file

@ -1,51 +0,0 @@
/* Simple Plugin API
* Copyright (C) 2016 Wim Taymans <wim.taymans@gmail.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#ifndef __SPA_BARRIER_H__
#define __SPA_BARRIER_H__
#ifdef __cplusplus
extern "C" {
#endif
#include <spa/defs.h>
#if defined(__GNUC__)
# if defined( __i386__ ) || defined( __i486__ ) || defined( __i586__ ) || defined( __i686__ ) || defined( __x86_64__ )
# define spa_barrier_full() asm volatile("mfence":::"memory")
# define spa_barrier_read() asm volatile("lfence":::"memory")
# define spa_barrier_write() asm volatile("sfence":::"memory")
# elif (__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1)
# define spa_barrier_full() __sync_synchronize()
# define spa_barrier_read() __sync_synchronize()
# define spa_barrier_write() __sync_synchronize()
# endif
#else
# warning no memory barriers support found
# define spa_barrier_full()
# define spa_barrier_read()
# define spa_barrier_write()
#endif
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif /* __SPA_BARRIER_H__ */

1
spa/include/spa/meson.build
View file

@ -1,6 +1,5 @@
spa_headers = [
'alloc-param.h',
'barrier.h',
'buffer.h',
'clock.h',
'command.h',

37
spa/include/spa/ringbuffer.h
View file

@ -32,7 +32,6 @@ typedef struct _SpaRingbuffer SpaRingbuffer;
#include <string.h>
#include <spa/defs.h>
#include <spa/barrier.h>
/**
* SpaRingbuffer:
@ -103,9 +102,8 @@ spa_ringbuffer_get_read_index (SpaRingbuffer *rbuf,
{
int32_t avail;
*index = rbuf->readindex;
avail = (int32_t) (rbuf->writeindex - *index);
spa_barrier_read();
*index = __atomic_load_n (&rbuf->readindex, __ATOMIC_RELAXED);
avail = (int32_t) (__atomic_load_n (&rbuf->writeindex, __ATOMIC_ACQUIRE) - *index);
return avail;
}
@ -138,18 +136,17 @@ spa_ringbuffer_read_data (SpaRingbuffer *rbuf,
}
/**
* spa_ringbuffer_read_advance:
* spa_ringbuffer_read_update:
* @rbuf: a #SpaRingbuffer
* @len: number of bytes to advance
* @index: new index
*
* Advance the read pointer by @len
* Update the read pointer to @index
*/
static inline void
spa_ringbuffer_read_advance (SpaRingbuffer *rbuf,
int32_t len)
spa_ringbuffer_read_update (SpaRingbuffer *rbuf,
int32_t index)
{
spa_barrier_full();
rbuf->readindex += len;
__atomic_store_n (&rbuf->readindex, index, __ATOMIC_RELEASE);
}
/**
@ -169,9 +166,8 @@ spa_ringbuffer_get_write_index (SpaRingbuffer *rbuf,
{
int32_t filled;
*index = rbuf->writeindex;
filled = (int32_t) (*index - rbuf->readindex);
spa_barrier_full();
*index = __atomic_load_n (&rbuf->writeindex, __ATOMIC_RELAXED);
filled = (int32_t) (*index - __atomic_load_n (&rbuf->readindex, __ATOMIC_ACQUIRE));
return filled;
}
@ -193,19 +189,18 @@ spa_ringbuffer_write_data (SpaRingbuffer *rbuf,
}
/**
* spa_ringbuffer_write_advance:
* spa_ringbuffer_write_update:
* @rbuf: a #SpaRingbuffer
* @len: number of bytes to advance
* @index: new index
*
* Advance the write pointer by @len
* Update the write pointer to @index
*
*/
static inline void
spa_ringbuffer_write_advance (SpaRingbuffer *rbuf,
int32_t len)
spa_ringbuffer_write_update (SpaRingbuffer *rbuf,
int32_t index)
{
spa_barrier_write();
rbuf->writeindex += len;
__atomic_store_n (&rbuf->writeindex, index, __ATOMIC_RELEASE);
}

2
spa/plugins/alsa/alsa-utils.c
View file

@ -372,7 +372,7 @@ pull_frames (SpaALSAState *state,
dst,
n_bytes);
spa_ringbuffer_read_advance (ringbuffer, n_bytes);
spa_ringbuffer_read_update (ringbuffer, index + n_bytes);
reuse = avail == n_bytes;
} else {
offs = SPA_MIN (d[0].chunk->offset + state->ready_offset, d[0].maxsize);

2
spa/plugins/audiotestsrc/audiotestsrc.c
View file

@ -324,7 +324,7 @@ audiotestsrc_make_buffer (SpaAudioTestSrc *this)
} else {
this->render_func (this, SPA_MEMBER (b->outbuf->datas[0].data, offset, void), n_samples);
}
spa_ringbuffer_write_advance (&b->rb->ringbuffer, n_bytes);
spa_ringbuffer_write_update (&b->rb->ringbuffer, index + n_bytes);
} else {
n_samples = n_bytes / this->bpf;
this->render_func (this, b->outbuf->datas[0].data, n_samples);