Re: gnu parallel mechanism

[Markus Bergholz]

On Sun, Jul 20, 2014 at 4:15 PM, Ole Tange <tange@gnu.org> wrote:

On Sun, Jul 20, 2014 at 4:02 PM, Markus Bergholz <markuman@gmail.com> wrote:
> Hi,
> I'd like to know what's behind gnu parallel? how does the parallelization
> works? It doesn't use openmp, does it?

Perl's open3 and fork.

Well, maybe that's interesting for you too

    time gm mogrify -resize 50% *.JPG

    real 3m57.774s

    time ls | parallel --no-notice -j "2" gm mogrify -resize 50% 

    real 3m45.902s

graphicsmagick is using openmp, but giving gm just 2x1 image with gnu parallel seems to be faster.

 

/Ole

--
icq: 167498924
XMPP|Jabber: markuman@jabber.ccc.de