[Python-Dev] Add a developer mode to Python: -X dev command line option

Antoine Pitrou antoine at python.org
Thu Nov 16 07:54:14 EST 2017

Hi Victor,

Thanks for the answer!

Le 16/11/2017 à 13:48, Victor Stinner a écrit :
> faulthandler has a negligible cost on performance/memory.
> For -W default, I guess that your question is the cost on emitting a
> warning: overhead when a warning is displayed, and overhead when the
> warning is filtered. Right?

-Wdefault means -Wonce or -Walways? If the former, I don't expect many
warnings to be emitted.

> For example, on test_os, PYTHONMALLOC=debug increases the peak memory
> usage from 10.5 MiB to 15.8 MiB: +50%.

I see.  For my use cases, this would be acceptable :-)

But I think this should be documented, for example:

"""Currently, developer mode adds negligible CPU time overhead, but can
increase memory consumption significantly if many small objects are
allocated.  This is subject to change in the future."""



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