Re: New Athlon Member

[R Clint Whaley <rwhaley@cs.utk.edu>]

>Gnu Compiler Collection (GCC) version 3. The most recent download I have is
>the 20010514 snapshot, and the Athlon build fails in GEMV, although the rest

I guess you've made sure it's not the error discussed here:
   http://www.netlib.org/atlas/errata.html#ATHLONdef

>1. I noticed there is a symbol definition implying a 512K L2 cache. Is this
>actually used, or does the code pick up the apparent cache size and use that?

It's used for cache flushing; for cache-optimizing parameters, ATLAS probes
the machine during the install.  Config actually has most of what you want
to understand, I think;  here's what it says about L2SIZE:
===============================================================================
This next value is the size, in kilobytes, that ATLAS must read/write in order
to completely flush your largest cache.  ATLAS will flush this much memory
between timing calls, in order to ensure timings are not inflated by
cache preloading.  A safe maximum is usually twice the size of your actual
largest cache size.  If you do not know the size of your largest cache,
a maximum value is fine.  The only drawback to making this value large
is that it requires more memory to do timings, and may slow down
the install process (if you have only a small amount of memory, it can also
invalidate the timings by causing the timers to swap).  The default given
below is ATLAS's idea of either the maximum cache your system could have, or
the maximum ATLAS believes it is safe to flush.  If you are certain that
your largest cache is smaller than the default given below, expedite the
install by changing it.  If you are certain you have enough memory to
support the necessary memory demands without swapping, and the value
is not twice the size of your largest cache, increase it.  Otherwise, just
hit enter to continue.
===============================================================================

>2. The configure step says it couldn't find the BLAS. I loaded everything on
>the Red Hat 7.1 CDs, which includes "liblapack and "libblas". There are BLAS
>libraries in "/usr/lib", and the R stat package, which also uses BLAS, builds
>successfully on this machine. Is there something I need to do to get the
>configure step to find the BLAS?

Hmm.  This is hard to answer without seeing why config didn't pick it up.
Config certainly looks in /usr/lib.  My guess is that the library is
incomplete in some way (vendors often leave out routines they don't use),
and so it won't pass config's link test.  During install, did you get
"Link failed /usr/lib/libblas.a rejected" or not?

Cheers,
Clint