User Guide

Contents

Cache Bound

Metric Description

This metric shows how often the machine was stalled on L1, L2, and L3 caches. While cache hits are serviced much more quickly than hits in DRAM, they can still incur a significant performance penalty. This metric also includes coherence penalties for shared data.

Possible Issues

A significant proportion of cycles are being spent on data fetches from caches. Check Memory Access analysis to see if accesses to L2 or L3 caches are problematic and consider applying the same performance tuning as you would for a cache-missing workload. This may include reducing the data working set size, improving data access locality, blocking or partitioning the working set to fit in the lower cache levels, or exploiting hardware prefetchers. Consider using software prefetchers, but note that they can interfere with normal loads, increase latency, and increase pressure on the memory system. This metric includes coherence penalties for shared data. Check Microarchitecture Exploration analysis to see if contested accesses or data sharing are indicated as likely issues.

Product and Performance Information

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Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804