[pymvpa] Time for single permutation varies between a few seconds and several minutes

Yaroslav Halchenko debian at onerussian.com
Wed Apr 8 12:55:10 UTC 2015

On Wed, 08 Apr 2015, Nick Oosterhof wrote:

> On 08 Apr 2015, at 14:03, Jan Derrfuss <derrfuss at gmail.com> wrote:

> > I'm stumped. I'm running a permutation for a searchlight analysis and print the time when the individual permutations start. I turns out that the onset times are sometimes mere seconds and sometimes several minutes apart.

> Very quick (and maybe silly) idea: could this be due to disk i/o? When running a multi-core searchlight, data is stored to disc and and then loaded by each child process. One possibility is that after a few children have started, different processes are competing for disk i/o, slowing everything down.

great idea... but unless you know what I don't know -- default
backend='native' so it doesn't go through files (once again -- we are
yet to see the code)

Yaroslav O. Halchenko, Ph.D.
http://neuro.debian.net http://www.pymvpa.org http://www.fail2ban.org
Research Scientist,            Psychological and Brain Sciences Dept.
Dartmouth College, 419 Moore Hall, Hinman Box 6207, Hanover, NH 03755
Phone: +1 (603) 646-9834                       Fax: +1 (603) 646-1419
WWW:   http://www.linkedin.com/in/yarik        

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