pthread_mutex in a winelib dll called from a win32 application

[Shachar Shemesh]

Mike Hearn wrote:

>On Wed, 21 Jul 2004 13:08:57 +0300, Shachar Shemesh wrote:
>  
>
>>Are there any restrictions in synchronizing wine generated threads 
>>(generated through the win32 api) using the pthreads library native calls?
>>    
>>
>
>On NPTL (pthread) systems I think this should work. On kthread systems
>pthreads is emulated by Wine anyway so you'd gain nothing.
>  
>
This is RedHat 9, kernel 2.4.20-31.9. It has NPTL, but we are not using 
it at the moment (LD_ASSUME_KERNEL=2.4.1). This does explain the 
problems we're having.

>>I have an app that is experiencing extremely slow performance (operation
>>takes 17 seconds on native windows, over 3 minutes on Wine). One idea
>>for solving this problem was to switch some of the synchronization
>>operations over to native pthreads (it's using wine as part of a
>>migration to Linux process).
>>    
>>
>
>Do you know for sure it's the synchro primitives that are causing the
>slowdown?
>
>  
>
Pretty much. We tried writing an app that does little else, and the same 
ratios were kept.

>>The problem is that when I try to call pthread_mutex_init,
>>pthread_mutex_lock and friends, I get quite a few deadlocks, and even
>>when not deadlocking, it still takes over 42 seconds. When doing the
>>same without the mutexes (I'm locking write access to a pipe - I'm not
>>sure it's even necessary, and it is working without the lock too), wine
>>performs at 21-26 seconds. I don't think that obtaining a posix mutex
>>should have such harsh effect on performance.
>>    
>>
>
>What kind of mutex are you using?
>
Already said - pthread_mutex_lock and friends.
Before, we were using Mutex and Event, with a call to 
"WaitForMultipleObjects".

> Critical sections should only RPC to the
>wineserver (which is the slow bit) when contended, iirc ... 
>  
>
How can you tell whether you are in contention without RPCing? That 
makes no sense to me. It's also not how I read the code.

>every time you block this involves a wineserver RPC so with high lock
>contention that could be a problem.
>
>thanks -mike
>  
>

          Shachar

-- 
Shachar Shemesh
Lingnu Open Source Consulting ltd.
http://www.lingnu.com/