Subject: Re: [linux-audio-dev] questions to be resolved
From: Karl MacMillan (karlmac_AT_peabody.jhu.edu)
Date: Mon May 21 2001 - 21:57:16 EEST
On Mon, 21 May 2001, Abramo Bagnara wrote:
> Abramo Bagnara wrote:
> >
> > readers and writer share the same memory that contains a copy of the
> > object and two integer: begin and end.
> >
> > writers:
> > pthread_mutex_lock
> > begin++
> > wmb()
> > write to the area
> > wmb()
> > end++
> > pthread_mutex_unlock
> >
> > reader:
> > if (cookie != end) {
> > cookie = end
> > rmb()
> > copy area to temp
> > rmb()
> > if (begin == end) {
> ^^^^^^^^^^^^^^
> sorry, typo cookie == begin
>
> > copy temp to object
> > do what needed
> > }
> > }
> >
> > Can I patent this? ;-))
> >
This has a large number of unnecessary buffer copies that probably will
not scale well. Have you looked at the other proposals that reduce buffer
copying?
Karl
> > > >> I don't understand the appeal (or the mechanics) or making interport
> > > >> connections be "internal" to a soundbox. The connections fundamentally
> > > >> alter the order in which a series of soundboxes must be "executed", so
> > > >> the engine must be able to fully determine the signal graph in order
> > > >> to accomplish correct execution of the graph. "correct" means "no
> > > >> cycle-duration delays between soundboxes unless there are feedback
> > > >> loops between them". So some aspect of the connections must be
> > > >> visible, at least to the engine.
> > > >
> > > >The engine knows everything about connections between its soundboxes,
> > > >but knows anything about connections internal to soundboxes.
> > >
> > > You wrote "connections are internal to a soundbox" apparently to
> > > indicate that you didn't follow why connections were visible at
> > > all. So I interpreted what you wrote to mean "connections are only
> > > internal to a soundbox".
> >
> > Some connections are internal to soundbox (if it contains other
> > soundboxes), others are at application level.
> >
> > --
> > Abramo Bagnara mailto:abramo_AT_alsa-project.org
> >
> > Opera Unica Phone: +39.546.656023
> > Via Emilia Interna, 140
> > 48014 Castel Bolognese (RA) - Italy
> >
> > ALSA project http://www.alsa-project.org
> > It sounds good!
>
> --
> Abramo Bagnara mailto:abramo_AT_alsa-project.org
>
> Opera Unica Phone: +39.546.656023
> Via Emilia Interna, 140
> 48014 Castel Bolognese (RA) - Italy
>
> ALSA project http://www.alsa-project.org
> It sounds good!
>
_____________________________________________________
| Karl W. MacMillan |
| Computer Music Department |
| Peabody Institute of the Johns Hopkins University |
| karlmac_AT_peabody.jhu.edu |
| mambo.peabody.jhu.edu/~karlmac |
-----------------------------------------------------
This archive was generated by hypermail 2b28 : Mon May 21 2001 - 22:20:03 EEST