Branch Mispredictions

Branch prediction misses are causing a significant negative performance impact and/or the branch prediction rate is low. If the performance impact metric is low, this issue may not be worth further investigation.

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 functions:

Branch Mispredict Performance Impact = ((Mispredicted Branches Retired*20)/Clockticks)*100
low value: 0.2
high value: 2

Branch Prediction Rate = (100-((Mispredicted Branches Retired/Branches Retired)*100))
low value: 75
high value: 95

This insight is relevant when Branch Mispredict Performance Impact is high or Branch Prediction Rate is low.

Advice:

Avoiding Branch Mispredictions