[PD-dev] per-thread storage in Pd in support of pdlib - discussion?

[Mathieu Bouchard]

Le 2012-01-19 à 01:09:00, Peter Brinkmann a écrit :

> As far as libpd is concerned, I would prefer not to have any 
> synchronization inside Pd itself --- libpd can be used in a wide variety 
> of settings, with lots of different approaches to concurrency, and so 
> it's impossible to make any assumptions about threading at this level.

If you avoid making any assumptions about threading inside Pd, then you 
can't share gensym and its static table with any other instance, because 
you can't ask all callers of gensym to do the locking on gensym. You can't 
ask each piece of software to do its own locking on gensym, because then 
they won't see each other's locks. Therefore, to share gensym, the locking 
must be inside gensym.

Sharing gensym is useful so that one can prepare lists and messages 
without having to lock everytime. This can allow to run the audio thread 
on one processor while cooking up a big list on the other processor. 
Otherwise the non-audio thread will get blocked even though the audio 
thread never even looks at the symtable.

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