Exploiting Spatial Locality
Besides capacity, granularities are important:
- Granularity of allocation
- Granularity of communication or data transfer
- Granularity of coherence
Major spatial-related causes of artifactual communication:
- Conflict misses
- Data distribution/layout (allocation granularity)
- Fragmentation (communication granularity)
- False sharing of data (coherence granularity)
All depend on how spatial access patterns interact with data structures
- Fix problems by modifying data structures, or layout/alignment
Examine later in context of architectures
- one simple example here: data distribution in SAS solver