me/portaudio
Watch
1
0
Fork
You've already forked portaudio
 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

memory barrier change take two

Browse source
This commit is contained in:
rossb 2011-08-18 11:47:28 +00:00
commit 6aa858c0f7
1 changed files with 7 additions and 9 deletions
Download patch file Download diff file Expand all files Collapse all files

16
src/common/pa_ringbuffer.c
View file

@ -127,10 +127,8 @@ ring_buffer_size_t PaUtil_GetRingBufferWriteRegions( PaUtilRingBuffer *rbuf, rin
*sizePtr2 = 0;
}
/* fixme: do we want a memory barrier here for write-after-read / acquire ?
if( available )
PaUtil_WriteMemoryBarrier(); / * (write-after-read? / acquire) * /
*/
PaUtil_FullMemoryBarrier(); /* (write-after-read) => full barrier */
return elementCount;
}
@ -140,8 +138,8 @@ ring_buffer_size_t PaUtil_GetRingBufferWriteRegions( PaUtilRingBuffer *rbuf, rin
*/
ring_buffer_size_t PaUtil_AdvanceRingBufferWriteIndex( PaUtilRingBuffer *rbuf, ring_buffer_size_t elementCount )
{
/* we need to ensure that previous writes are seen before we update the write index
(write after write / release)
/* ensure that previous writes are seen before we update the write index
(write after write)
*/
PaUtil_WriteMemoryBarrier();
return rbuf->writeIndex = (rbuf->writeIndex + elementCount) & rbuf->bigMask;
@ -180,7 +178,7 @@ ring_buffer_size_t PaUtil_GetRingBufferReadRegions( PaUtilRingBuffer *rbuf, ring
}
if( available )
PaUtil_ReadMemoryBarrier(); /* (read-after-read / acquire) */
PaUtil_ReadMemoryBarrier(); /* (read-after-read) => read barrier */
return elementCount;
}
@ -188,10 +186,10 @@ ring_buffer_size_t PaUtil_GetRingBufferReadRegions( PaUtilRingBuffer *rbuf, ring
*/
ring_buffer_size_t PaUtil_AdvanceRingBufferReadIndex( PaUtilRingBuffer *rbuf, ring_buffer_size_t elementCount )
{
/* ensure that previous reads (copies out of the ring buffer) are always completed before updating the read index.
(write-after-read / release)
/* ensure that previous reads (copies out of the ring buffer) are always completed before updating (writing) the read index.
(write-after-read) => full barrier
*/
PaUtil_WriteMemoryBarrier();
PaUtil_FullMemoryBarrier();
return rbuf->readIndex = (rbuf->readIndex + elementCount) & rbuf->bigMask;
}