Re: Solving the problem of mutual recursion

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From	Ian Kelly <ian.g.kelly@gmail.com>
Date	2013-05-27 01:04 -0600
Subject	Re: Solving the problem of mutual recursion
Newsgroups	comp.lang.python
Message-ID	<mailman.2238.1369638314.3114.python-list@python.org> (permalink)

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On Mon, May 27, 2013 at 12:19 AM, Ian Kelly <ian.g.kelly@gmail.com> wrote:
> 7) Since the program being tested does basically nothing except start
> and exit threads, the extra 40% probably represents the overhead of
> all that starting and stopping, which would be done outside the GIL.

To test this, I tried running the script in Python 2.7 in Linux with
the print statements removed and verified that it was using about 135%
of the CPU.  However, top also told me that only about 95% of that was
user processes; the other 40% was kernel usage.  The 40% doesn't seem
to be threading overhead though, because I tried adding large xrange
loops to slow down the thread creation process and it had no effect on
the stats.

Then I tried running the same program in Python 3.2, and I got the
more expected 100% CPU usage with minimal kernel time.  So I'm
thinking now that the extra 40% may actually be overhead induced by
the GIL.  If that's the case then wow, the old GIL really did suck.

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Thread

Solving the problem of mutual recursion Peter Brooks <peter.h.m.brooks@gmail.com> - 2013-05-26 04:49 -0700
  Re: Solving the problem of mutual recursion Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-05-26 18:09 +0300
    Re: Solving the problem of mutual recursion Roy Smith <roy@panix.com> - 2013-05-26 11:23 -0400
    Re: Solving the problem of mutual recursion Peter Brooks <peter.h.m.brooks@gmail.com> - 2013-05-26 10:21 -0700
      RE: Solving the problem of mutual recursion Carlos Nepomuceno <carlosnepomuceno@outlook.com> - 2013-05-26 21:09 +0300
        Re: Solving the problem of mutual recursion Peter Brooks <peter.h.m.brooks@gmail.com> - 2013-05-26 11:13 -0700
          RE: Solving the problem of mutual recursion Carlos Nepomuceno <carlosnepomuceno@outlook.com> - 2013-05-26 21:22 +0300
            Re: Solving the problem of mutual recursion Peter Brooks <peter.h.m.brooks@gmail.com> - 2013-05-26 12:05 -0700
          Re: Solving the problem of mutual recursion Ian Kelly <ian.g.kelly@gmail.com> - 2013-05-26 13:35 -0600
          Re: Solving the problem of mutual recursion Chris Angelico <rosuav@gmail.com> - 2013-05-27 08:16 +1000
            Re: Solving the problem of mutual recursion Peter Brooks <peter.h.m.brooks@gmail.com> - 2013-05-26 21:36 -0700
              Re: Solving the problem of mutual recursion Ian Kelly <ian.g.kelly@gmail.com> - 2013-05-27 00:07 -0600
              Re: Solving the problem of mutual recursion Chris Angelico <rosuav@gmail.com> - 2013-05-27 17:37 +1000
          Re: Solving the problem of mutual recursion Ian Kelly <ian.g.kelly@gmail.com> - 2013-05-27 00:19 -0600
          Re: Solving the problem of mutual recursion Ian Kelly <ian.g.kelly@gmail.com> - 2013-05-27 01:04 -0600

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