[linux-audio-dev] lock-free data structures

[Tim Hockin]

On Thu, Jun 17, 2004 at 08:22:29PM -0700, Joshua Haberman wrote:
> One final thing: I'm not sure if this is a problem in practice, but 
> most (if not all) processors do not guarantee that memory reads and 
> writes are performed in order, as observed by other processors and by 
> I/O devices.  This could theoretically lead to a problem where the 
> stores that write data to the ring buffer are not performed until 
> *after* the store that updates your write pointer.  Your reader thread 
> could get old data rather than the data your just wrote.  To guarantee 
> that the loads and stores are observed in the required order, you have 
> to use memory barriers (again, in theory).  See:

Yes, this was discussed here a while back. For all practical platforms
that the developers cared about, 32 bit aligned access are atomic.

They are not guaranteed to STAY that way, but for now..