[Python.NET] AcquireThreadLock - bug? future?

bksasha at zahav.net.il bksasha at zahav.net.il
Mon Mar 14 17:00:40 CET 2005


Greetings

I think this may be tye reason why I can successfuly cal any property from
Zope, but any function call except constructor hangs the instance

Can there be some option to treat methods like properties also, so product
become usable from Zope?

Thanks
Alexander

----- Original Message ----- 
From: "Brian Lloyd" <brian at zope.com>
To: "Roman Yakovenko" <roman.yakovenko at gmail.com>; <pythondotnet at python.org>
Sent: Monday, March 14, 2005 2:07 PM
Subject: RE: [Python.NET] AcquireThreadLock - bug? future?


> Essentially the engine needs to own the thread lock in
> order to call Python C API functions. When a (managed)
> method is called, the MethodBinder:
>
>   - releases the lock (so that other threads could
>     potentially run)
>
>   - calls the managed method
>
>   - re-acquires the lock after the call (because it
>     needs to use the C API again to Pythonify the
>     result, etc.)
>
> So it sounds like some thread is unable to re-acquire
> the lock. This gets tricky _really_ quickly, because
> you can actually be calling a managed object that may
> later call back into Python code... etc.
>
> Note that this doesn't happen for properties, because I
> arbitrarily decided that since properties are expected to
> to be lightweight that it wasn't worth the overhead ;)
>
>
> Brian Lloyd        brian at zope.com
> V.P. Engineering   540.361.1716
> Zope Corporation   http://www.zope.com
>
>
> > -----Original Message-----
> > From: pythondotnet-bounces at python.org
> > [mailto:pythondotnet-bounces at python.org]On Behalf Of Roman Yakovenko
> > Sent: Monday, March 14, 2005 1:24 AM
> > To: pythondotnet at python.org
> > Subject: [Python.NET] AcquireThreadLock - bug? future?
> >
> >
> > Hi. I have small problem with multithreading and need help to solve it.
> > I have dll written in managed C++. Within dll I have class that has
> > static function. I'd like to call this function from a few threads
> > from python. I failed to do this. Calling function staled and this is
> > a stack dump from debugger ( of my program )
> >
> > python.runtime.dll!Python.Runtime.PythonEngine.AcquireThreadLock()
> >  + 0x40 bytes
> >
> > python.runtime.dll!Python.Runtime.MethodBinder.Invoke(int inst =
> > 11793552, int args = 9900080, int kw = 0) + 0xf0 bytes
> >
> > python.runtime.dll!Python.Runtime.MethodObject.Invoke(int target =
> > 11793552, int args = 9900080, int kw = 0) + 0x25 bytes
> >
> > python.runtime.dll!Python.Runtime.MethodBinding.tp_call(int ob =
> > 11794928, int args = 9900080, int kw = 0) + 0x137 bytes
> >
> > I don't understand:
> >     1. Why Python.Net tries to acquire thread lock, while calling
> > function ?
> >         I am possible to call get property from a few threads. From
> > managed C++ point of view ( I could be wrong here ) getting value of
> > property it is just syntax sugaring for get_??? call. I want to say
> > that if I able to call "get property" from a few threads I should be
> > able to call function from a few threads.
> >     2. Why at all Python.Net tries to synchronize function calls?
> >
> > I can modify and compile source code of Python.Net, but I know to
> > little about reasons
> > of calling AcquireThreadLock.
> >
> > Thanks for help
> >
> > Roman
> > _________________________________________________
> > Python.NET mailing list - PythonDotNet at python.org
> > http://mail.python.org/mailman/listinfo/pythondotnet
> >
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