serialize() slow
On Sat, Aug 21, 2010 at 2:16 PM, Fernando Saldanha <fsaldan1 at gmail.com> wrote:
In this post: http://www.mail-archive.com/r-devel at r-project.org/msg13248.html Henrik Bengtsson observes that the R function serialize() can run very slowly when the argument connection is null and provides a function serialize2() that runs much faster. The post is dated 7/24/2008. Some code I wrote using package Rmpi was running slowly and I found out the bottleneck was exactly the function serialize(), which is called by some functions in Rmpi. So I inserted the command serialize <- serialize2 in my code and there was a dramatic acceleration of the relevant portions of the program.
If serialize2 fixes it for you, doesn't that answer your own question? You ask why the different computers may perform differently. Can I ask if there is any chance you have been fiddling around with alternative BLAS? I see a huge horrible Rmpi slowdown when GOTOBLAS2 is installed with threads allowed > 1. I had not heard of the serialize/serialize2 thing you mention, but I'm interested to try it to see what effect it has. I will let you know if I see any difference.
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