Igor Stasenko wrote:
> There are already some steps done in this direction. A sources for
> RISC architecture generate a foo struct , which holds all interpreter
> globals.
> Also, i did some changes in Exupery to create a single struct of all
> VM globals (not only variables, but functions too).
> This was done to make it easier to get address of any global symbol
> what Exupery needs.
> I'm also experimented to replace all direct calls to function to
> indirect (i.e. foo->primAdd(x,y) instead of primAdd(x,y)). This caused
> about ~1% of speed degradation in tinyBenchmarks :)

Ah, indeed, I forgot about that.

> Also, moving forward on this renders an InterpreterProxy struct
> useless, because we can just pass an address to our 'foo' struct to
> plugins which already contains everything what plugin can reach.

But this isn't quite true. One of the reasons for the proxy is to 
abstract from the actual implementation since C doesn't do proper name 
lookup for names but rather uses indexes. And so, if you happen to add 
or remove a method from that struct, your plugins will be screwed ;-)

>> The above takes care about the interpreter but there are still
>> primitives and plugins that need to be dealt with. What I would do here
>> is define operations like ioLock(struct VM) and ioUnlock(struct VM) that
>> are the effective equivalent of Python's GIL (global interpreter lock)
>> and allow exclusive access to primitives that have not been converted to
>> multi-threading yet. How exactly this conversion should happen is
>> deliberately left open here; maybe changing the VMs major proxy version
>> is the right thing to do to indicate the changed semantics. In any case,
>> the GIL allows us to readily reuse all existing plugins without having
>> to worry about conversion early on.
>>
> Or as i proposed in earlier posts, the other way could be to schedule
> all primitive calls, which currently don't support multi-threading to
> single 'main' thread.
> Then we don't need the GIL.

I had missed that. Yes, that would work just as well.

Cheers,
   - Andreas