On 11 May 2016 at 22:51, Ethan Furman <et...@stoneleaf.us> wrote: > On 05/11/2016 01:44 PM, Serhiy Storchaka wrote: > > os.path >>> ''''''' >>> >>> The various path-manipulation functions of ``os.path`` [#os-path]_ >>> will be updated to accept path objects. For polymorphic functions that >>> accept both bytes and strings, they will be updated to simply use >>> code very much similar to >>> ``path.__fspath__() if hasattr(path, '__fspath__') else path``. This >>> will allow for their pre-existing type-checking code to continue to >>> function. >>> >> >> I afraid that this will hit a performance. Some os.path functions are >> used in tight loops, they are hard optimized, and adding support of path >> protocol can have visible negative effect. >> > > Do you have an example of os.path functions being used in a tight loop? >
os.path.getmtime could be used in a tight loop, to sync directories with a lot of files for instance. % python3 -m timeit -s "import os.path; p = 'out'" "hasattr(p, '__fspath__'), os.path.getmtime(p)" 100000 loops, best of 3: 2.67 usec per loop % python3 -m timeit -s "import os.path; p = 'out'" "isinstance(p, (str, bytes)), os.path.getmtime(p)" 100000 loops, best of 3: 2.45 usec per loop % python3 -m timeit -s "import os.path; p = 'out'" "os.path.getmtime(p)" 100000 loops, best of 3: 2.02 usec per loop a 25% markup is a lot imo. a isinstance check prior to the hasattr might be a way to mitigate this a bit (but it doesn't help much) Granted, this example could be optimised by calling os.stat directly, which is not in os.path, but still, worth considering
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