Edward Elliott <[EMAIL PROTECTED]> wrote: > Alex Martelli wrote: > > about MacOSX, which also uses gcc: 14% faster pybench using Python 2.4.3 > > this is the second time I've seen that 14% figure. OOC, where does it come > from? the data sets you posted show an average 12.6% speedup. 14 is an > odd way to round. :)
I believe 12.6% is the result if you pick the faster speed as a denominator (and so it's the right figure for a _slowdown_, hypothetically moving from fast to slow case), 14% if you pick the slower speed as a denominator (i.e., for a _speedup_). Of course if you work with times rather than speeds it's the other way around. > I don't think it's very useful to talk about average speedups from a > benchmark of equally-weighted feature tests. the data shows wildly varying > differences in performance for each test. a real-world application could > be much slower or much faster on either platform depending on its feature > mix. not the type of thing that's amenable to expression as a single > value. I believe the single figure is a useful summary. Even the most sophisticated benchmarks are eventually boiled down to single figures, as in "so many SPECmarks" etc, because in everyday discourse a scalar is what you can reasonably discuss. Sure, philosophically speaking it makes no sense to say that a compiler is better or worse than another at optimization, without adding a lawyer's brief worth of qualifications each and every time. In real life, it's a useful and practical temporary simplification, and engineers (as opposed to mathematicians and philosophers) have a bias towards practical usefulness. Alex -- http://mail.python.org/mailman/listinfo/python-list
