On Mon, Apr 14, 2014 at 3:51 PM, Brett Cannon <bcan...@gmail.com> wrote: > It was realized during PyCon that since we are freezing importlib we could > now consider freezing all the modules to cut out having to stat or read them > from disk. So for day 1 of the sprints I I decided to hack up a > proof-of-concept to see what kind of performance gain it would get. > > Freezing everything except encodings.__init__, os, and _sysconfigdata, it > speeds up startup by 11% compared to default. Compared to 2.7 it shaves 14% > from the slowdown (27% slower vs. 41% slower). The full results are at the > end of the email.
Nice. I was hoping it would be even bigger (given the hyper-focus people put on the impact of FS-access on startup time imports), but this is definitely a significant improvement. I wonder then where the remaining slowdown lies; are there any remaining low hanging fruit elsewhere? > > Now the question is whether the maintenance cost of having to rebuild Python > for a select number of stdlib modules is enough to warrant putting in the > effort to make this work. Yeah. Definitely the big question. Who cares the most about startup time? Would this improvement please them? Does that alone make it worth the increased maintenance burden? Is that group big enough or important enough to justify it? At the very least it may be good for the PR value alone, but the maintenance cost will long outlive the PR benefit. :) > My guess is the best approach would be adding a > Lib/_frozen directory where any modules that we treat like this would be > kept to act as a reminder that you need to rebuild for them (I would > probably move importlib/_boostrap.py as well to make this consistent). That makes sense. I also wonder if we could accomplish the same thing with a marker (e.g. a comment) in each related module (and leave them where they are). A marker would allow for easily finding the freezable modules. Personally, I think the speedup would be worth it if it doesn't add significant to the maintenance burden. -eric _______________________________________________ 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/archive%40mail-archive.com
