Intel cache Address

Question

Here is the L3 cache (shared) configuration on my Intel Xeon Silver 4210R CPU-

$ getconf -a | grep LEVEL3_CACHE
LEVEL3_CACHE_SIZE                  14417920
LEVEL3_CACHE_ASSOC                 11
LEVEL3_CACHE_LINESIZE              64

This configuration implies that the number of sets in the cache is-

Now I am trying to understand the addressing of the cache .

Here, the cache line (or the block) size is 64 bytes and intel uses the byte-addressable system. Therefore, the least significant bits of cache address should be used for block offset.

With a similar calculation, the number of address bits that should be used for set indexing is , but this fraction value confuses me.

Am I missing something? How many bits are exactly used here for set indexing?

Answer 1

Am I missing something?

This processor has 10 cores — your formula doesn't account for # of cores, so if you divide by 10 it is an even multiple of 2.

How many bits are exactly used here for set indexing?

11 bits, I believe

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L3$ 13.75 MiB 10x1.375 MiB 11-way set associative write-back

read more here: https://en.wikichip.org/wiki/intel/xeon_silver/4210r