On Fri, Mar 6, 2015 at 1:11 PM, Brett Cannon <br...@python.org> wrote:
> > > On Fri, Mar 6, 2015 at 1:03 PM Mark Shannon <m...@hotpy.org> wrote: > >> >> On 06/03/15 16:34, Brett Cannon wrote: >> > Over on the import-sig I proposed eliminating the concept of .pyo files >> > since they only signify that /some/ optimization took place, not >> > /what/ optimizations took place. Everyone on the SIG was positive with >> > the idea so I wrote a PEP, got positive feedback from the SIG again, and >> > so now I present to you PEP 488 for discussion. >> > >> [snip] >> >> Historically -O and -OO have been the antithesis of optimisation, they >> change the behaviour of the program with no noticeable effect on >> performance. >> If a change is to be made, why not just drop .pyo files and be done with >> it? >> > > I disagree with your premise that .pyo files don't have a noticeable > effect on performance. If you don't use asserts a lot then there is no > effect, but if you use them heavily or have them perform expensive > calculations then there is an impact. And the dropping of docstrings does > have an impact on memory usage when you use Python at scale. > > You're also assuming that we will never develop an AST optimizer that will > go beyond what the peepholer can do based on raw bytecode, or something > that involves a bit of calculation and thus something you wouldn't want to > do at startup. > I don't want to speak for him, but you're going to get the best results optimizing ASTs at runtime, which is what I thought he was suggesting. Trying to optimize Python at compile time is setting your sights really low. You have so little information then. > > >> >> Any worthwhile optimisation needs to be done at runtime or involve much >> more than tweaking bytecode. >> > > I disagree again. If you do something like whole program analysis and want > to use that to optimize something, you will surface that through bytecode > and not editing the source. So while you are doing "much more than tweaking > bytecode" externally to Python, you still have to surface to the > interpreter through bytecode. > > _______________________________________________ > Python-Dev mailing list > Python-Dev@python.org > https://mail.python.org/mailman/listinfo/python-dev > Unsubscribe: > https://mail.python.org/mailman/options/python-dev/mistersheik%40gmail.com > >
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