New patches to speed up R 2.13.0

I have now released a new collection of 30 patches to speed up R version 2.13.0. You can get them here

Assessing how much these patches speed up R is difficult. First of all, the speedup varies tremendously with the type of program. It also varies quite a bit with the machine and compiler used to run R. Finally, it varies in apparently random ways — changing code in one part of the R interpreter can change the speed of operations that never use the modified code by plus or minus 5% or more.  This is presumably due to the change altering the exact addresses of other code segments, with consequent effects on alignment of memory fetches or on cache behaviour.

Nevertheless, here is a comparison of R 2.13.0 without modification and with all my patches applied, with and without compilation of R functions. The tests were done with an Intel X5680 processor running at 3.33GHz in 64-bit mode using gcc 4.4.4 under Red Hat Linux with default R configuration parameters. The tests use my suite of speed tests for R.

Here are some highlights:

Under the slide