Analyze Loop Call Count

Accuracy Level

Medium

Enabled Analyses

Survey + Trip Counts (Characterization)

Result Interpretation

After you run the Vectorization and Code Insights perspective with medium accuracy and Trip Counts collection enabled, Intel® Advisor dynamically identifies the number of times loops are invoked and execute and extends the basic vectorization report with the Trip Counts data. Use Trip Counts data to analyze parallelism granularity more deeply and fine-tune vector efficiency and capability.

By default, the Trip Counts column shows only Average and Call Count metrics. Look for the following to find good candidates for optimization:

• Detect loops with too-small trip counts and trip counts that are not a multiple of vector length.
• A high number in the Call Count column means there is an outer loop in the selected loop call chain with high trip count values.
• If the loop has a low trip count value, the outer loop could be a better candidate for parallelization (threading/vectorization).

To optimize such loops, follow the Intel® Advisor Recommendations for the loop/function, for example, use specific recommended pragmas to provide the information about loop trip counts to a compiler.

Next Steps

For further investigation, you can run the Vectorization and Code Insights perspective with a higher accuracy level or with different configurations:

• Examine Not-Vectorized and Under-Vectorized Loops
• Investigate Memory Usage and Traffic
• Find Data Dependencies