David Xu wrote:
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 set mutex's member field m_type to
PTHREAD_MUTEX_ADAPTIVE_NP by your change, so how can it work as
expected ?
mysql does:
#ifdef PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP
/*
Set mutex type to "fast" a.k.a "adaptive"
In this case the thread may steal the mutex from some other thread
that is waiting for the same mutex. This will save us some
context switches but may cause a thread to 'starve forever' while
waiting for the mutex (not likely if the code within the mutex is
short).
*/
pthread_mutexattr_init(&my_fast_mutexattr);
pthread_mutexattr_settype(&my_fast_mutexattr,
PTHREAD_MUTEX_ADAPTIVE_NP);
#endif
Kris
_______________________________________________
cvs-all@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/cvs-all
To unsubscribe, send any mail to "[EMAIL PROTECTED]"
