[Bf-committers] Bledner 2.5 - futex problem

[Nathan Letwory]

Jacob Heller wrote:
> Has anyone else experienced problems associated with the futex system in
> 2.5?  When using blender, it will lock-up at seemingly random moments.
> I haven't found any particular pattern as to what makes it freeze and it
> usually happens after 2-10 minutes of using it, but I've gone 45 minutes
> at some points before it happens.  Absolutely nothing responds when it
> freezes, not even the "close" button at the top of the window.
>   
> Interestingly, Ubuntu will not even give me the "This window looks like
> it's frozen, press here to force quit" dialogue.  I have to go the
> system monitor and kill the task.  Looking at the System Monitor when it
> happens, under "Waiting channel" it always says "futex_wait" which leads
> me to believe it has to do with blender's mutex/futex system.  I'm no
> expert at this, but it seems like the multithreading system is mutually
> locking any of blender's processes from proceeding.  Blender will not
> consume any CPU resources when it freezes.

I'm not sure if I'm the right person to answer here, but at least for 
the sake of not having this thread get lost in the bithistory of the ML. 
Anyway, from what I know, we don't use any futexes explicitely. I don't 
know if pthreads on Linux does something behind the scenes to play with 
those...

Maybe some hardcore Linux user under our developers can have a peek into 
this and maybe shed some light on this? GSR maybe?

/Nathan

> 
> I have confirmed this on two different systems.  Below are the specs:
> 
> Pentium Quad Core Q6600, 2.4 GHz
> 4 Gb RAM
> Nvidia 9800 GT
> Ubuntu Linux, 64 Bit
> 
> Centrino Dual Core, 2.0 Ghz
> 2 Gb RAM
> Nvidia 7900 Go
> Ubuntu Linux, 32 Bit
> 
> -Jake
> 
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-- 

Nathan Letwory

http://www.planetblender.org | http://www.blender-fi.org