[Rd] does parLapplyLB do load-balancing?

Chris Paciorek paciorek at stat.berkeley.edu
Sat Dec 6 02:36:00 CET 2014

Looking at parLapplyLB, one sees that it takes in X and then passes
splitList(X, length(cl)) to clusterApplyLB, which then calls
dynamicClusterApply.  Thus while dynamicClusterApply does handle tasks
in a load-balancing fashion, sending out individual tasks as previous
tasks complete, parLapplyLB preempts that by splitting up the tasks in
advance into as many groups of tasks as there are cluster processes.
This seems to defeat the purpose of load-balancing and of the manner
in which dynamicClusterApply is coded.

This question basically repeats a question posed in 2013 -- see

I'm reposting because there doesn't seem to have been any response to
the previous posting, and it looks like the issue is still present in
R 3.1 so it seems asking again if this is the intended behavior of

I'm using R 3.1.1 and the 3.1.1 version of the parallel package under
Ubuntu 14.04, but the code appears to be the same in R-devel.


Chris Paciorek

Statistical Computing Consultant
Statistical Computing Facility, Econometrics Laboratory, Berkeley
Research Computing

Office: 495 Evans Hall                      Email: paciorek at stat.berkeley.edu
Mailing Address:                            Voice: 510-842-6670
Department of Statistics                    Fax:   510-642-7892
367 Evans Hall                              Skype: cjpaciorek
University of California, Berkeley          WWW:
Berkeley, CA 94720 USA                      Permanent forward:
paciorek at alumni.cmu.edu

More information about the R-devel mailing list