Daniel Dittmar wrote: > robert wrote: >> (IPython is only a special "python network terminal" as already said.) > > Sorry, I thought of IronPython, the .NET variant. > >> Does Jython really eliminate the GIL? What happens when different > > Yes. > >> threads alter/read a dict concurrently - the basic operation in >> python, which is usually not protected by locks. Does Jython use a >> dict data type (and other collection types) which lock during _each_ >> access? in case - that may be very expensive. > > True, though Java synchronization has gotten better and better. Still, > Sun introduced non locking hash tables, so it was a problem. It'd be > interesting to know which kind of dict is used in Jython for attribute > access.
I hate Jave :-) , but to come to concerns of this thread, the speed. Found not much about. http://mail.zope.org/pipermail/zpt/2002-March/002884.html says Jython to be at least 9x slower. Is this still the gap (and constant locking a big factor in this). IronPython seems to be surprisingly faster than CPython (sometimes): http://www.python.org/pycon/dc2004/papers/9/ But I cannot imagine, that this includes GIL free locking dicts an all ... !? Is numpy/scipy available for Iron/Jython ? >> garbage is collected earliest, when the refcount went to 0. If it ever >> went to 0, no one will ever use such object again. Thus GC should not >> be different at all. > > Since Python 2.?, there's a mark-and-sweep garbage collection in > addition to the reference counting scheme. This was put into Python to > be able to reclaim object cycles. still that only walks on objects which have already zero refcount. Cannot imagine any additional problems with the GIL. robert -- http://mail.python.org/mailman/listinfo/python-list
