Replacements into the L1D.
This metric shows how often machine was stalled on L2 cache. Avoiding cache misses (L1 misses/L2 hits) will improve the latency and increase performance.
Replacements into the L2.
This metric shows how often CPU was stalled on L3 cache, or contended with a sibling Core. Avoiding cache misses (L2 misses/L3 hits) improves the latency and increases performance.