Re: how do a RISC compiler translate an array initialization ?

In comp.arch Sid Ahmed Ali TOUATI <Sid-Ahmed-Ali.TOUATI@inria.fr> wrote:
: [Sounds like the cache lines are bigger than individual words, and these
: chips may have a write-behind cache. -John]


He took the cache line behavior into account. (REAL is 8 bytes, 200 of
them is 50 cache lines for a 32 byte line.) More likely the issue has
to do with how the performance counters work with respect to write
misses. A quick test is to measure the run time of the loop posted and
a loop which stores the constant to the same variable over and over
again. Checking the compiler output of course to make sure the stores
is not optimized away. In C/C++ you can declare the variable volatile
to defeat compiler optimization. I do not know if there is a similar
mechanism in FORTRAN.


-Z-

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