[simspark-devel] Fwd: about multi-thread implementation

[Yuan X. <xuy...@gm...>]

Hi Hedayat and all,



 >
 >  Yes :(. But Mesa might be thread safe now. Since I've installed nvidia
 > binary drivers, simspark uses nvidia OpenGL libraries instead of using Mesa.
 > So, I can't say anything about mesa, but nvidia opengl is not thread safe.
 >


The rcssserver3d-0.5.6 can run multi-threads in my computer, it does
 not need to call opengl in the main thread. but the cvs head code
 can't.
 It is very strange, so I decide to look into this problem.

 Because there are too many differences between cvs head and 0.5.6,
 I copy the barrier implementation to the rcssserver3d-0.5.6,
 then it works! while calling opengl in a new thread.
 I attached the testing server to this mail, could you test it in your system?

 So, the problem may caused by other changes relative to opengl,
 I tested and compared the of functions in class rendercontrol and
 rendernode, they should be OK.
 Thus, I think the problem may caused by the initialization of opengl,
 but the ruby scripts are changed a lot, I do not have time to trace them now.



 >
 >  The interesting (not much!) point is that I have not encountered any
 > problems by calling mSceneServer->PrePhysicsUpdate() in
 > parallel till now! Is there any conflicts between
 > mSceneServer->PrePhysicsUpdate() and EndCycle() functions
 > in the current code?!
 >


I am not sure, but they may conflict after future changing.
 I changes a little with your code.( See the package attached.)
 I hope it would be OK.

 There is another issue should be in mind is that
 the multi-threads increase the sense act latency,
 it makes agent behavior unlike in the singled-thread.
 I think this will make teams in trouble while changing from
 singled-thread to multi-threads.
 What do you think about it?


 --
 Best wishes!

 Xu Yuan
 School of Automation
 Southeast University, Nanjing, China

 mail:   xuy...@gm...
          xy...@ya...
 web:   http://xuyuan.cn.googlepages.com
 --------------------------------------------------