[M] Change in coreboot[master]: drivers/mrc_cache: Compare hashes instead of full data

[Reka Norman (Code Review)]

Attention is currently required from: Kangheui Won.

Reka Norman has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/67670 )

Change subject: drivers/mrc_cache: Compare hashes instead of full data
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Patch Set 2:

(1 comment)

Commit Message:

https://review.coreboot.org/c/coreboot/+/67670/comment/9ee49949_ff242816 
PS2, Line 18: 14 ms on uncached data on nissa
> The fact that this is 14ms both here and below is pretty conspicuous. […]

Good point, I did assume basically all the time was spent reading from memory, but I didn't think about the byte-by-byte vs 32-bit difference.

xxhash is still faster with caching (see the patchset 1 commit message). But as Tim commented this is probably because of OOO execution.