In short, it's impossible to use Gnu Pth library with impalad "AS IS", i.e. without modification.
Gnu Pth:
- Gnu Pth can't fully replace
pthreads. It lacks some functions, some entities. - It doesn't provide versioned symbols
There are some *.so libraries (system/thirdparty) which come precompiled and they are linked against versioned symbols. Be prepared to recompile them replace somehow or just do anything. Example:
- libjvm.so (oracle jre)
- libhdfs.so (feel free to find sources)
- librt.so (system one)
- boost.so
They also may use (and actually, do so) some features Gnu Pth doesn't provide (semaphores as most striking example, there is pth fork with semaphores, though).
Today i tried to force compile executor with pth instead of pthread. First, I was able to reduce the number of undefined reference's when linking with pth via this Version file:
GLIBC_2.2.5 {
pthread_create;
pthread_join;
pthread_detach;
pthread_attr_setstacksize;
pthread_attr_getstacksize;
pthread_attr_getstack;
pthread_setspecific;
pthread_barrier_init;
pthread_cancel;
sem_destroy;
pthread_create;
pthread_getattr_np;
pthread_key_create;
pthread_key_delete;
pthread_sigmask;
sem_trywait;
__pthread_get_minstack;
pthread_attr_setguardsize;
sem_wait;
sem_post;
sem_timedwait;
pthread_condattr_setclock;
sem_init;
pthread_once;
pthread_mutex_trylock;
pthread_join;
pthread_kill;
__pthread_unwind;
pthread_barrier_wait;
pthread_getspecific;
};
Also, i make pthread_detach as weak alias for __pthread_detach which is present in pth.
Remaining undefined reference's come from:
- librt.so
- libjvm.so
- libhdfs.so
- libthrift.a
They address features not present in pth.
I still have no idea about how version-ed symbols should work and created. I tried creating dummy shared library referencing pthread. It also reference symbols with @GLIBC suffix. It seems that they come from linker when linking target shared library.