multicore, mclapply memory problem
On 29/06/2012 07:59, Fabrice Tourre wrote:
Dear list, I am using mclapply(from multicore) to use multiple cores on one server. If I do not use mclapply, just one core, my R problem will use 4G memory. When I use mclapply and set mc.cores =10, each core will use 4G memory. So totally it will use 40G memory. Is it possible let each core to share some memory on the same server?
Well, actually it does this automatically .... On a decent OS (despite the posting guide, you did not tell us yours), forking will share pages between the forked copies until the page is changed. So in particular any large R objects created before forking will remain shared between the worker processes. And BTW, package multicore was superseded by parallel last year.
Brian D. Ripley, ripley at stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595