Le Mon, 10 Dec 2012 18:17:57 -0500, Raymond Hettinger <raymond.hettin...@gmail.com> a écrit : > > On Dec 10, 2012, at 2:48 AM, Christian Heimes <christ...@python.org> > wrote: > > > On the other hand every lookup and collision checks needs an > > additional multiplication, addition and pointer dereferencing: > > > > entry = entries_baseaddr + sizeof(PyDictKeyEntry) * idx > > > Currently, the dict implementation allows alternative lookup > functions based on whether the keys are all strings. > The choice of lookup function is stored in a function pointer. > That lets each lookup use the currently active lookup > function without having to make any computations or branches.
An indirect function call is technically a branch, as seen from the CPU (and not necessarily a very predictable one, although recent Intel CPUs are said to be quite good at that). Regards Antoine. _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
