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cachingbuffercpu-architectureevict
user2927392
user2927392

Reputation: 251

What are Fill/Evict buffers

Arm A72 core TRM specifies that L1 has a 'fill buffer' and that L2 has a 'fill/evict queue' and the manual does not mention anywhere what they do. Am I right in assuming the following

  1. Fill buffer is something that temporarily holds a cache line before it is loaded onto the cache (but why?)
  2. Evict queue buffers a cache line when it is evicted from the cache and before it is written back to the memory.

Upvotes: 0

Views: 367

Answers (1)

Peter Cordes
Peter Cordes

Reputation: 364009

Probably a "fill buffer" is something that waits for / tracks the incoming cache line between sending out a request and the data coming back. Loads from that cache line can attach themselves to it, so they get notified when data comes back (so it can get written to registers and, if needed, forwarded to instructions waiting to read those registers).

That's what Line Fill Buffers do in Intel CPUs. (Although in Intel CPUs, LFBs are used for stores as well.)

Upvotes: 0

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