x87 Output Assists

Assists require micro code assistance which can cause a significant performance penalty. Note: Using the latest compilers will usually fix this problem.

For systems with the Hyper-Threading Technology enabled or multi-processor systems, the estimated impact represents the total processor time impact (added across all logical/physical processors on the system), and not the "wall-clock" time impact. Therefore, on a system with the Hyper-Threading Technology enabled or multi-processor system, it is quite possible to see an insight having an impact greater than the workload wall-clock run time. Note that on a UP system, processor time is the same as wall-clock time.

Counter dependencies:

This insight is dependent on the following performance counter function:

x87OutputAssists Performance Impact = ((x87 Output Assists*650)/Clockticks)*100
low value: 0.2
high value: 2

This insight is relevant when x87OutputAssists Performance Impact is high.

Advice:

Avoiding x87 Denormals