8 Nov
2007
8 Nov
'07
9:35 a.m.
David Olofson <david(a)olofson.net> writes:
On Thursday 08 November 2007, Stefano D'Angelo
wrote:
[...]
It is quite possible that some other plugin may need arbitrary size
chunks. It is just that lv2zynadd does not need such (to my current
knowledge about Paul's synth). And the point is whether arbitrary sized
chunk memory functionality should be exposed as separate extension or in
same one with pool based.
I'm not a plugin developer and I have nothing
to do with LV2, but
anyway I think it can be a useful thing and that it is good to have
one "standard protocol" for this in LV2, instead of letting plugins
rely on external libraries or, even worse, include their own rt-safe
memory allocator.
Yes, that's exactly my point, but I think it needs to deal with
arbitrary size chunks to actually be able to serve that purpose in
real applications.
To avoid plugins effectively allocating private pools (just as if
they'd implemented it internally), a host would have to use a proper
real time memory manager, and then, whey not just make that available
directly to plugins? BTW, are the blocking allocation calls intended for
background
threads...?
So far they are used during plugin instantiation. Background threads
should probably be exposed as another extension if some plugin needs
them.
Wouldn't it be more useful with some interface
that allows plugins to
request memory in a non-blocking manner, and if instant allocation
fails, have the host notify the plugin when the memory is available?
Basically, a malloc() call that means "If I can't have this memory
right away, please expand the pool so I can have it later!"
The alternative would be to use the blocking version
only
in "background" threads, but unless you need background threads
anyway, to do actual work, this is just moving complexity into
plugins for no gain. If a plugin wants some memory to play around
with "in the near future", it shouldn't have to implement it's own
asynchronous memory management just to avoid stalling the host's
audio thread.
With pool/lv2dynparam approach, you say min preallocated chunks greater
than zero. And make your algorithms retry call operation next time
(allocate new voice).
IMO, point of plugins is to have complexity moved from lots of plugins
to fewer hosts. And preferably packaged as libraries to ease code reuse
(as it is with lv2dynparam libs).
--
Nedko Arnaudov <GnuPG KeyID: DE1716B0>