[Python-Dev] Request for inclusion in 2.5.2 (5-for-1)

Guido van Rossum guido at python.org
Fri Nov 2 14:57:49 CET 2007


On 10/31/07, Mike Klaas <mike.klaas at gmail.com> wrote:
> Issue http://bugs.python.org/issue1663329 details an annoyance in the
> subprocess module that has affected several users, including me.
> Essentially, closing hundreds of thousands of file descriptors by
> round-tripping through the python exception machinery is very slow,
> taking hundreds of milliseconds and at times many seconds.  The
> proposed fix is to write this loop in c.  The c function is but a
> handful of lines long.  I purposefully kept the implementation
> trivial so that it will work on all unix variants (there is another
> issue that contains a super-duper optimization for AIX, and other
> possibilities exist for Solaris, but the simple fix yields a ten-fold
> speedup everywhere but windows, so I didn't think that it was worth
> the complexity).
>
> Though technically relating only to performance, I consider this a
> bug-fix candidate as mysterious multi-second delays when launching a
> subprocess end up making the functionality of close_fds unusable on
> some platform configurations (namely, those with high MAX_FD set).
>
> It would be great to see this is 2.5.2.  Understanding that issue
> evaluation takes significant effort, I've done some evaluation/triage
> on other open tickets:

Thanks for doing these!

Since people are already jumping on those bugs but nobody has voiced
an opinion on your own patch, let me say that I think it's a good
patch, and I want it in 2.6, but I'm reluctant to add it to 2.5.2 as
it goes well beyond a bugfix (adding a new C API and all that).

-- 
--Guido van Rossum (home page: http://www.python.org/~guido/)


More information about the Python-Dev mailing list