Re: GNU Parallel Bug Reports Parallel is slower and results a bit different

[Martin Møller Skarbiniks Pedersen]

On 23 February 2012 16:46, Jose Pablo Barrantes <xjpablobrx@gmail.com> wrote:
> Hi, on my computer:
>
> $ uname -a
> Linux dell-17 3.2.6-2-ARCH #1 SMP PREEMPT Thu Feb 16 10:23:00 UTC 2012 i686
> Intel(R) Core(TM) i7-2630QM CPU @ 2.00GHz GenuineIntel GNU/Linux
>
> whenever I try the following:
>
> jp@d$ time find . -name '*.el' | parallel ls -la | wc -l
> 5345
>
> real 0m13.176s
> user 0m40.714s
> sys 0m16.039s
> jp@d$ time find . -name '*.el' | xargs  ls -la | wc -l
> 5347

I guess it is just because everything from the find is cache from the first run.

Try run the xargs version first and the parallel version after and see
if you get reverse results.

And then try to flush all caches between each run.
as root:
echo 3 > /proc/sys/vm/drop_caches

/Martin