[Beignet] I met heavy memory leaks while using beignet library.

[Rebecca N. Palmer]

https://bugs.launchpad.net/ubuntu/+source/pyopencl/+bug/1354086

It may help to wait for one run of the kernel to finish before starting 
the next: for me, repeated pyopencl.enqueue_copy(cq0,bCL.data,aCL.data) 
leaks memory (sometimes ending in a crash, sometimes a whole-system 
hang) but repeated pyopencl.enqueue_copy(cq0,bCL.data,aCL.data).wait() 
doesn't.

Also note that frequently creating and deleting objects may be slow 
(compared to reusing existing ones) even when it doesn't crash.