Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.python > #90382

Re: Calling a function is faster than not calling it?

Show all headers | View raw

[Multipart message — attachments visible in raw view] - view raw

On Mon, May 11, 2015 at 4:50 AM, BartC <bc@freeuk.com> wrote:

> You just seem surprised that using eval() to do this is slower than a
> direct call.


Well, it is surprising. Most uses of eval() are to evaluate Python
expressions in string form. That I expect to be quite slow, given the
parsing+byte compilation overhead. I wouldn't expect eval()ing a code
object to be all that different than calling the function containing the
code object.

My guess (without looking in ceval.c) is that the code path through the VM
has been tweaked heavily over the years to try and speed it up. Except for
places where that path overlaps with the path for eval(code_object), I
doubt any attention has been paid to speeding up eval. I could certainly be
way off-base here. Perhaps the path taken through the interpreter for
eval(code_object) is more-or-less a subset of the path taken for a simple
function call.

Skip

Back to comp.lang.python | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

Calling a function is faster than not calling it? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-05-10 19:58 +1000
  Re: Calling a function is faster than not calling it? Christian Gollwitzer <auriocus@gmx.de> - 2015-05-10 12:34 +0200
    Re: Calling a function is faster than not calling it? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-05-11 01:04 +1000
  Re: Calling a function is faster than not calling it? Peter Otten <__peter__@web.de> - 2015-05-10 12:43 +0200
    Re: Calling a function is faster than not calling it? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-05-11 00:49 +1000
      Re: Calling a function is faster than not calling it? Peter Otten <__peter__@web.de> - 2015-05-10 18:14 +0200
      Re: Calling a function is faster than not calling it? Ian Kelly <ian.g.kelly@gmail.com> - 2015-05-10 10:25 -0600
  Re: Calling a function is faster than not calling it? Terry Reedy <tjreedy@udel.edu> - 2015-05-10 12:37 -0400
  Re: Calling a function is faster than not calling it? BartC <bc@freeuk.com> - 2015-05-10 22:08 +0100
    Re: Calling a function is faster than not calling it? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-05-11 13:58 +1000
      Re: Calling a function is faster than not calling it? BartC <bc@freeuk.com> - 2015-05-11 10:50 +0100
        Re: Calling a function is faster than not calling it? Skip Montanaro <skip.montanaro@gmail.com> - 2015-05-11 09:12 -0500
          Re: Calling a function is faster than not calling it? BartC <bc@freeuk.com> - 2015-05-11 16:01 +0100
            Re: Calling a function is faster than not calling it? Skip Montanaro <skip.montanaro@gmail.com> - 2015-05-11 10:13 -0500
      Re: Calling a function is faster than not calling it? Tony the Tiger <tony@tiger.invalid> - 2015-05-15 01:35 +0000
  Re: Calling a function is faster than not calling it? Stefan Behnel <stefan_ml@behnel.de> - 2015-05-11 08:11 +0200
  Re: Calling a function is faster than not calling it? Piet van Oostrum <piet@vanoostrum.org> - 2015-06-22 23:49 +0200

csiph-web