Immutable and cache coherence

[bearophile]

Tomek S.:

> is there a way to exclude immutable regions of memory from a cache 
> coherence mechanism? I mean, let the processor know: no invalidation for cache lines from 
> immutable memory.

I don't know the answer, but regarding cache coherence and immutable data, if your data structure (like a graph) is immutable, then it doesn't need free spaces and data necessary to allow its growth. So you are often able to pack it more in memory, and this saves some RAM and reduces cache misses, improving performance too.

Bye,
bearophile