On Sun, 05 Feb 2006 16:14:54 +0000, Neil Schemenauer wrote: > Steven D'Aprano <[EMAIL PROTECTED]> wrote: >> Have you actually measured this, or are you just making a wild >> guess? > > I haven't timed it until now but my guess it not so wild. I'm > pretty familiar with the generator implementation (having written > the initial version of it).
Well I guess you're forgiven then *sheepish grin* > In Python 2.3, resuming a generator > does a small amount of setup and then calls eval_frame(). Calling a > function does more setup work and then also calls eval_frame(). It takes MORE setup to call a function than it takes to resume a generator? >> Here is my test, using Python 2.3. I've tried to make the test as >> fair as possible, with the same number of name lookups in both >> pieces of test code. > > On my machine t4 is faster than t3. Your test is not so fair > because the generator is doing a "while" loop (executing more > bytecode instructions) while the function is just returning a value > (one instruction). A fair criticism, but then a generator with just one instruction is, well, pointless. > On your machine the function call may be faster due to CPU cache > effects or branch prediction. In any case, the difference you are > trying to measure is extremely small. Try adding some arguments to > the functions (especially keyword arguments). Small in absolute terms, but significant in relative terms: as an order of magnitude, a factor of about 1/10th. Of course, I never expected that calling/resuming cost to be significant for most real world uses. If I gave anyone that impression, it wasn't intended. > What your test does show is that the speed difference should not > come into the decision of which construct to use. I never said it should. -- Steven. -- http://mail.python.org/mailman/listinfo/python-list
