Mark Fletcher wrote on 5/12/20 9:55 AM: > On Tue, May 12, 2020 at 08:16:52AM -0600, D. R. Evans wrote: >> Mark Fletcher wrote on 5/12/20 7:34 AM: >>> Hello >>> >> >> I have noticed that recent versions of R supplied by debian are using all the >> available cores instead of just one. I don't know whether that's a debian >> change or an R change, but it certainly makes things much faster (one of my >> major complaints about R was that it seemed to be single threaded, so I'm >> very >> glad that, for whatever reason, that's no longer the case). >> > Thanks, but definitely not the case here. When running on my own > machine, top shows the process at 100% CPU, the load on the machine > heading for 1.0, and the Gnome system monitor shows one CPU vCore > (hyperthread, whatever) at 100% and the other 7 idle. > > R is certainly _capable_ of using more of the CPU than that, but you > have to load libraries eg snow and use their function calls to do it -- in > short, like in many languages, you have to code for parallelism. I tried > to keep parallelism out of this experiment on both machines being > compared. >
OK. Well I don't understand what's going on and don't really have anything further to contribute :-( All I know is that the same code that used to run on just one core pre-buster now uses all the cores available, with no changes or fancy libraries. I was (of course) very pleasantly surprised the first time I ran one of my R scripts under buster and saw this happen. I haven't experimented further. Doc -- Web: http://enginehousebooks.com/drevans
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