[Bug 11674] Dual-core not being correctly supported in World of Warcraft (WOW)

[wine-bugs at winehq.org]

http://bugs.winehq.org/show_bug.cgi?id=11674





--- Comment #10 from Claudiu Curca <Alexstrasza2 at gmail.com>  2009-01-06 07:44:54 ---
(In reply to comment #7)
> (In reply to comment #6)
> > This suggests that the problem may be the way in which threading is implemented
> > in World of Warcraft, but to study this is kinda out of my reach. 
> > 
> 
> 
> Either that it could be that either WoW decides not to schedule as much work as
> it does on Windows
> 
> I don't know if it'll be useful, but maybe something can be spotted if you add
> traces to dlls/kernel32/thread.c for some of the functions which don't have
> traces (CreateThread, SuspendThread, ResumeThread, SetThreadPriority,
> SetThreadPriorityBoost, SetThreadAffinityMask, SetThreadIdealProcessor) which
> print the function parameters using the TRACE macro then attach a +thread,+tid
> log here.
> 

I've followed your advice and dug a bit deeper. Unfortunately, I found out a
sad thing. 

By the looks of it, World of Warcraft does NOT use multiple threads for
rendering or analysis during gameplay. I started the game, entered the world
and played for a few minutes.

As you can see from the snippet of the status of the threads yielded by "ps
alm", only ONE thread has been using CPU time (the one with 5:29). The rest are
clearly there, but they are not used for extensive operation.

But then why does it work on Windows? I think i can answer that too.

By looking at the snippet of the wine log you can see that there's one specific
thread that's being thrown from one CPU to the other (using the
SetThreadAffinityMask function). On windows this might cause the "illusion"
that 2 threads are actually using one core each. I might be wrong, but I don't
know how else to demonstrate the windows behavior.

I will try to install wine on a windows machine (if i can get one) and see if
the behavior is the same. Maybe it can shed a bit more light on the subject.


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