2 Nov
2005
2 Nov
'05
9:23 a.m.
Le 2 nov. 05 à 14:05, Alfons Adriaensen a écrit :
On Wed, Nov 02, 2005 at 01:57:47PM +0100, St?phane
Letz wrote:
Yes, don't use named semas, but 'anonymous' ones placed in memory
shared by all clients. Each new client gets two pointers, one to the
sema it has to wait on (fixed for the client's lifetime), and one it
has to signal (changes when the graph is reordered).
But in a data flow model, a given client may have to signal several
semaphores. And the client that actually signals the semaphore is
only known at activation time. For the following graph for example :
--> A
IN --> C
--> B
where A and B can run in parallel, C is activated by the *last*
client of A and B that finish its processing. Thus A and B have to
"know" the C semaphore.
More generally a given client would have to keep a set of semaphores
it may have to signal for a given graph topology. This could improve
the N*N issue but is more difficult to handle.
So if
there are N clients, each of them needs N file descriptors
open
all the time. System wide the complexity grows as N^2. Not really a
good way to tackle an O(N) problem IMHO.
Yes but in the jackdmp data flow kind of model, the actual activation
order is only known when the graph executes.
Or do you have a better idea to do that?
But of course if OSX doesn't have them, then it's impossible...
And OSX does not support them, so i guess we will keep the current
(simple...) implementation in jackdmp until the problem you describe
becomes a real one in real situations...
Stephane