Re: --round-robin and --keep-order with --pipe

[Ole Tange]

On Sat, Aug 10, 2013 at 11:50 PM, Ole Tange <tange@gnu.org> wrote:

> I am considering letting --round-robin become default for --pipe, and
> let --keep-order mean --not-round-robin.
>
> That will mean that the default will not start one job per block, but
> instead on job per CPU. Only when running --keep-order a job per block
> will be started - and the order of the output will be fixed.
>
> Can you find situations where this change of default will cause problems?

One case came up: If GNU Parallel is used as a filter for an infinite stream:

  cat /dev/urandom | parallel --pipe cat | running_statistics

If --pipe defaulted to --round-robin, GNU Parallel would have to cache
the full output of all the 'cat's causing $TMPDIR to run full.

So that seems like a bad idea.


/Ole