On Monday 16 January 2012 11:34:53 Matthias Bolte wrote:
Okay, without looking deeper into this here are some ideas:
The XPCOM API libvirt uses might not be threadsafe, or needs to be initialized for every thread that wants to use it. Currently its only initialized for the thread that opens the driver. I know that this is the case on Windows were VirtualBox uses MSCOM for its API and you need to call CoInitialize on every thread. This is currently not done for the MSCOM glue in libvirt, so I know that on Windows the VirtualBox driver is not threadsafe currently. Also I didn't look into a solution for this yet. Maybe we need a thread local variable that holds whether (MS/XP)COM was already initialized for this thread and add a check to every driver function to initialize it when needed.
Did you try to open a connection for each thread instead of trying to share one? If that works reliable it might indicate that there is an VirtualBox API initialization problem.
I tried today with one connection for each thread and it works. I changed the vbox driver so that the pfnComInitialize function is called only when the first connection is opened : it breaks the test, even with one connection per thread. I guess we'll have to use a thread local variable as you suggested, unless someone has a better idea to handle this problem. -- Jean-Baptiste ROUAULT Ingénieur R&D - diateam : Architectes de l'information Phone : +33 (0)2 98 050 050 Fax : +33 (0)2 98 050 051