Figure 6-6, Pass 1 pass 2 pass 3 pass 4 – Intel ARCHITECTURE IA-32 User Manual

Page 325

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Optimizing Cache Usage

6

6-35

In the temporally-adjacent scenario, subsequent passes use the same
data and find it already in second-level cache. Prefetch issues aside, this
is the preferred situation. In the temporally non-adjacent scenario, data
used in pass m is displaced by pass (m+1), requiring data re-fetch into
the

first level cache

and perhaps the second level cache if a later pass

reuses the data. If both data sets fit into the second-level cache, load
operations in passes 3 and 4 become less expensive.

Figure 6-6

Cache Blocking – Temporally Adjacent and Non-adjacent Passes

Dataset A

Dataset B

Dataset B

Dataset A

Dataset A

Dataset A

Dataset B

Dataset B

Pass 1

Pass 2

Pass 3

Pass 4

Temporally

adjacent passes

Temporally

non-adjacent

passes

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