This depends on what else is going on. My guess is that you are running the Aqua GUI, and it is servicing the GUI which is taking the time, not R itself.
On all of Linux, Solaris and Windows (RGui or Rterm) Sys.sleep() does use very close to zero resources at the beginning of a session, but things may be different if e.g. tcltk widgets are in use. On Fri, 29 Jul 2005, Don MacQueen wrote: > I done something very similar -- have R watch a file, and whenever > new data is added to the file, read the new data from the file. In my > case, new data was arriving once per minute, so I needed to have R > wait about a minute before looking for new data. > > On my unix-based system, I found that if I usd I don't think your system IS `unix-based' (Unix is a trademark, and MacOS X is based on a rather different kernel). It is quite possible that it is behaving differently from the POSIX description of Unix system calls on which R is based for Unix-alikes. > Sys.sleep( N ) > then cpu usage immediately went up drastically. If the the system is > otherwise fairly idle, cpu usage goes up to nearly 100%. A cpu > monitor shows that R is using the cpu cycles. > > If I use instead > system('sleep N') > cpu usage does not go up. Does that freeze the GUI? It certainly freezes tcltk widgets on Unix. > (where N is the number of seconds to sleep) > >> version > _ > platform powerpc-apple-darwin7.9.0 > arch powerpc > os darwin7.9.0 > system powerpc, darwin7.9.0 > status > major 2 > minor 1.1 > year 2005 > month 06 > day 20 > language R > > > At 12:13 PM -0700 7/29/05, Tae-Hoon Chung wrote: >> Hi, All; >> >> I have a question. In R, what is the best way to make R idle for a while and >> try something again later? For example, suppose there is an R job which >> accesses a file that may be shared with other active jobs. So when the file >> is being accessed by other job, your job will not be able to access the file >> and your job will crash because of that. To avoid this, you want your job to >> try to access the file repeatedly with some time interval, say every 10 >> seconds or something like that. Which is the best way to do this in R? -- Brian D. Ripley, [EMAIL PROTECTED] 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 ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html