[LAD] a *simple* ring buffer, comments pls?

Paul Davis paul at linuxaudiosystems.com
Sun Jul 10 21:41:19 UTC 2011


On Sun, Jul 10, 2011 at 5:14 PM, Fons Adriaensen <fons at linuxaudio.org> wrote:

> On that I absolutely agree - cache coherency is the real
> problem, not pipelining. The latter should in fact be
> transparent from a language such as C/C++.

i may be way out of the loop, but having worked with some of the early
"massively" parallel "conventional processor" systems of the late 80's
and early 90's (such as the sequent symmetry and the kendall square
research machines), my impression was that everyone gave up on
"clever" cache coherency because it turned out to be too hard (as an
engineering problem, not as a CS problem). i've gotten stuck with the
idea that the industry went for "simple" cache coherency that simply
does what any moderately skilled designer would do when faced with the
problem and no concerns about elegance or speed: locks, signalling,
and all the usual stuff that is the h/w equiivalent of the pthreads
mutex API.

do we have SMP systems these days that do not guarantee cache coherency?

btw: i do understand that whether they do or do not doesn't affect the
basic point about cache coherency possibly leading to incorrect data
being read.



More information about the Linux-audio-dev mailing list