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Foil 54 Cray T3E Cache Structure

From Master Foilset for HPC Achitecture Overview CPS615 Introduction to Computational Science -- Fall Semester 1998. by Geoffrey C. Fox

Interesting Article from SC97 proceedings on T3E performance
Each CRAY T3E processor contains an 8 KB direct-mapped primary data cache (Dcache), an 8 KB instruction cache, and a 96 KB 3-way associative secondary cache (Scache) which is used for both data and instructions.
The Scache has a random replacement policy and is write-allocate and write-back, meaning that a cacheable store request to an address that is not in the cache causes that address to be loaded into the Scache, then modified and tagged as dirty for write-back later.
Write-back of dirty cache lines occurs only when the line is removed from the Scache, either by the Scache controller to make room for a new cache line, or by the back-map to maintain coherence of the caches with the local memory and/or registers.



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