cvs commit: src/lib/libthr/thread thr_mutex.c src/lib/libkse/thread thr_mutex.c src/include pthread.h

[David Xu]

Kris Kennaway wrote:
> 
> PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP is just in <pthread.h>.
> 
> /*
>  * Static initialization values.
>  */
> #define PTHREAD_MUTEX_INITIALIZER       NULL
> #define PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP   NULL
> #define PTHREAD_COND_INITIALIZER        NULL
> #define PTHREAD_RWLOCK_INITIALIZER      NULL
> 
>>>> I remembered mysql uses this macro to initialize spin mutex, and you
>>>> indead needs a patch to let it work
>>>
>>>
>>> No, with the code I committed mysql detects and uses it out of the 
>>> box, without requiring any patches.  It is easy to measure the 
>>> resulting 30% performance improvement at high loads ;-)
>>>
>> see above, I didn't see any code set PTHREAD_MUTEX_ADAPTIVE_NP type.
> 
> The code is already in mysql for use with glibc.  It basically does
> 
> #ifdef PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP
> /*
>  * Use PTHREAD_MUTEX_ADAPTIVE_NP for the mutexes we know will benefit
>  * from it
>  */
> ...
> #endif
> 
> so it just works.
> 

I can not find code in libthr setting mutex's member field m_type to
PTHREAD_MUTEX_ADAPTIVE_NP by your change, so how can it work as
expected ?