[R] Performance difference between 32-bit build and 64-bit bu ild on Solaris 8

[Scott Gilpin]

Andy, Prof. Ripley - thanks for your replies.

> CFLAGS was not specified, so should default to "-g -O2".  It is definitely
> worth checking, although almost all the time in these tests will be spent
> in Fortran code.
Yes - I verified that's the default.

> >> neither build uses a BLAS.
> 
> Well, they do, the one supplied with R (which is in Fortran).

I guess I should have said that neither build is using an optimized
BLAS.  (which I am planning to install - I just haven't had the chance
yet.)   I also get a message in config.log "ld: fatal: library -lblas:
not found".  I need to investigate this more.


> and for gcc 3.4.3 and the internal BLAS (which I had to build for these
> tests) I get
> 
> 32-bit
> [1]  9.96  0.09 10.12  0.00  0.00
> 64-bit
> [1]  9.93  0.04 10.04  0.00  0.00
> 
> so I am not seeing anything like the same performance difference between
> 32- and 64-bit builds (but it could well depend on the particular Sparc
> chip).

These timings are much, much less than what I reported (~700s and
2200s for 32 bit and 64 bit).  I read the admin manual and didn't see
anything specifically that needs to be set to use the internal BLAS.  
I guess I'll go back and do some more investigation.

Thanks for your help.