Re: [R] Rcpp and mclapply

2013-10-10 Thread Jeff Newmiller
I cannot imagine how the calling process will affect this. If you want further help I think you will need to provide a reproducible example and info as requested by the Posting Guide. --- Jeff Newmiller

Re: [R] Rcpp and mclapply

2013-10-10 Thread sophie_brugieres
Dear Jeff, I had suspected something along those lines initially, however, as I had stated, this only happens sometimes ... Here is a partial top showing two of my calls: 17404 sophie20 0 12.4g 11g 1996 R 100 4.6 5:50.11 R 17405 sophie20 0 12.4g 11g 2016 R 100 4.6 5:49.86 R

Re: [R] Rcpp and mclapply

2013-10-10 Thread Jeff Newmiller
I would bet that you are doing something in C++ that shares some resource between the workers and blocks all but one worker at a time. --- Jeff NewmillerThe . . Go Live... DCN:

[R] Rcpp and mclapply

2013-10-10 Thread sophie_brugieres
Dear all, I have an R script that uses Rcpp, and I have been trying to parallelize it using mclapply (I tried with the multicore and the parallel library) Sometimes (not always, interestingly), the CPU use for each core drops, usually so that the total over all cores reaches 100%, i.e., as fast a