Liaw, Andy
2003-Nov-25 21:18 UTC
64-bit R on Opteron [was Re: [R] Windows R 1.8.0 hangs when M em Usage >1.8GB]
> From: Douglas Bates [mailto:bates at bates4.stat.wisc.edu] > > "Liaw, Andy" <andy_liaw at merck.com> writes: > > > Sorry. I need to retract my claim. There seems to be a 3G > limit, even > > though the OS could handle nearly 8G. (I can have two > simultaneous R > > processes each using near 3G.) > > > > On another note, on our dual Opteron box R (compiled as > 64-bit) could easily > > use nearly all the 16G in that box (that's one of the > reason for having that > > box). > > Does "could" mean you have verified that it did or is this a > theoretical statement? I.e., have you compiled and tested R on your > dual Opteron?Given my questionable memory of things, this question is very fair. Here's the evidence:> x <- matrix(0, 5e5, 5e5) > x2 <- matrix(0, 5e5, 5e5) > gc()used (Mb) gc trigger (Mb) Ncells 413379 22.1 741108 39.6 Vcells 1783900405 13610.1 1784288128 13613.1 Best, Andy
Douglas Bates
2003-Nov-25 23:07 UTC
[Rd] Re: 64-bit R on Opteron [was Re: [R] Windows R 1.8.0 hangs when M em Usage >1.8GB]
(Reply moved to R-devel where it may be more appropriate.) "Liaw, Andy" <andy_liaw@merck.com> writes:> > From: Douglas Bates [mailto:bates@bates4.stat.wisc.edu] > > > > "Liaw, Andy" <andy_liaw@merck.com> writes: > > > > > Sorry. I need to retract my claim. There seems to be a 3G > > > limit, even though the OS could handle nearly 8G. (I can have > > > two simultaneous R processes each using near 3G.) > > > > > > On another note, on our dual Opteron box R (compiled as 64-bit) > > > could easily use nearly all the 16G in that box (that's one of > > > the reason for having that box). > > > > Does "could" mean you have verified that it did or is this a > > theoretical statement? I.e., have you compiled and tested R on your > > dual Opteron? > > Given my questionable memory of things, this question is very fair. > Here's the evidence: > > > x <- matrix(0, 5e5, 5e5) > > x2 <- matrix(0, 5e5, 5e5) > > gc() > used (Mb) gc trigger (Mb) > Ncells 413379 22.1 741108 39.6 > Vcells 1783900405 13610.1 1784288128 13613.1Amazing! I wonder if R&R thought when they started out that they would one day see something like that. How does the Opteron perform on floating point? Can you try something like> mm = matrix(rnorm(1e6), nc = 1e3) > system.time(crossprod(mm))[1] 0.51 0.02 0.53 0.00 0.00> system.time(crossprod(mm))[1] 0.37 0.03 0.40 0.00 0.00> system.time(crossprod(mm))[1] 0.38 0.02 0.40 0.00 0.00> system.time(crossprod(mm))[1] 0.38 0.02 0.40 0.00 0.00 (That was with R compiled to use Goto's BLAS on a 2.0 GHz P4.) Are you using Goto's BLAS or Atlas?
Reasonably Related Threads
- 64-bit R on Opteron [was Re: Windows R 1.8.0 hangs when M em Usage >1.8GB]
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