Re: DU Libraries and such

[Greg Lindahl <lindahl cs virginia edu>]

> 1. I thought that a lot of the performance improvements seen under
>    Digital Unix were due to a better libm implementation.  Does anyone
>    have an idea of how much is attributable to DEC C vs egcs (say) &
>    how much is attibutable to the *implementation* of libm?

The new linux libm is about as fast or faster than Digital's. Since
SPECfp doesn't use libm, 100% of the differences I saw on SPECfp are
due to compiler quality. I suspect that with better instruction
scheduling, most of the difference will go away. There are good test
cases such as FFTW, which is a library with huge basic blocks of fp
operations. egcs doesn't schedule this well and is 2x slower than DU's
Fortran compiler.

-- g