[LAD] memory allocation for the real time thread, opinions wanted

Hi everyone, hoping to get opinions from gurus on here, who have been
*incredibly* helpful in getting my project to where its at. A million thank
yous!

Ok, the situation so far, which is working well:
- the app uses a generalized 'message' structure, all the different forms
of messages fit into this structure by having it act alike a union. ( ie, a
message always takes up the same amount of space, no matter the type )
- messages do not container pointers, in order that they be simple to send
and receive over network clients, hardware, etc
- there are ringbuffers between my audio thread and real time thread

What I'm tackling:
- I want to add the capability for messages to have deferred execution, so
they can be sent with a 'process at 4:3:1' kind of thing
- I think the best tradeoff for my app so far will be to use a hybrid of a
timeline array and a linked list. there will be coarse time values stored
by raw array indexing, speeding up lookup, and fine time values will be
stored in the messages themselves
- so, when the engine is processing deferred messages, it will go and check
timelineArray for all messages at bar 1:beat 1, which will be a linked list
of all the messages with start time between bar:1 beat 1 and bar 1: beat 2
( time resolution may change, this just for example
- then the engine iterates on every tick through that list of messages.
This way, iteration on every tick is limited to a reasonable sized linked
list and I can play with the cpu vs data storage equation by simply
changing the resolution of the time line array

Issues:
- I need to allocate memory for new linked list items in the realtime thread
- the timeline array needs to be able to grow in the real time thread

Thoughts:
- I don't need to get it perfect *right now* but I need to be able to
change it to Really Good later
- I checked out some resources, like this one the Design Patterns for *Real*
-*Time* Computer *Music*
Systems<http://www.google.ca/url?sa=t&rct=j&q=audio%20allocating%20memory%20in%20real%20time%20thread&source=web&cd=3&ved=0CDIQFjAC&url=http%3A%2F%2Fwww.cs.cmu.edu%2F%7Erbd%2Fdoc%2Ficmc2005workshop%2Freal-time-systems-concepts-design-patterns.pdf&ei=g1xJT66mEYvOiALDnN3oAQ&usg=AFQjCNET-FI8lrlYfnIBP39Dwr-GLDptrA&sig2=f5fUXFebwZ6MpOcF2tYJug&cad=rja>
and the supercollider book chapter and see there are a lot of options
- I could pre-allocate a giant list of messages and pluck the data off that
list when I need to make a new one
- I could pre-allocate a block of memory and allocate off that
- I could allocate in the non-realtime thread and then pass memory over in
queues.

Would love to hear opinions on how others would solve these, including
tradeoffs of each.

thanks!
iain

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Received on Sun Feb 26 00:15:04 2012