Re: benchmark programs

gxj@dcs.ed.ac.uk (Graham Jones) wrote:
>I am doing some simulations into latency hiding techniques and I would like
>to find some benchmarks which either
>
> 1) prove difficult for caches


Gabriel's "Performance & Evaluation of LISP Systems", early 80's, had LISP
source for a number of benchmarks including multiple variants of a viciously
recursive but otherwise trivial function called tak. At least one variant was
deliberately designed to defeat cache.


// omitting details I don't recall offhand
tak(unsigned x,y,z)
{
            if(x<y)
                          return z ;
            else // recurse, calling tak 4 times
                          return( tak(
                                                          tak( ), // arguments here are permutations
                                                          tak( ), // of x,y,z
                                                          tak( ) // with some x-1's mixed in
                                                        ) ;
}


The cache-defeating variant had some large number of copies of this function,
like tak000 to tak999, and made the recursion call different copies in a
random order.
--

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