Stalls Report
Overview
This report gives the raw stall count values for each instrumentation counter, grouped by stage. That is to say, each "main" row is a row in the stage latency report, while the blow table gives information about different counter attached to one of the buffers going into or out of that stage. For the main rows, please see the stage latency report. The columns of the table are as follows:
Read the output data
| Column Name | Meaning |
|---|---|
kind |
Either STALL_RD0 or STALL_RD1 |
unit_name |
Name of the unit containing the instrumentation counter |
value |
Raw instrumentation counter count |
csr_value_before |
Register value before the instrumentation counter is started by the stall event |
csr_value |
Raw instrumentation counter count |
Locate the report
The report is provided to you in .XLSX format at the following location in your output folder:
/reports/collated_report.xslx in the 'Stalls' worksheet.
View the report in the GUI
The SambaTune GUI displays the table of stalls for every stage in every section executed on the RDU. Here are examples of table reports available on the SambaTune GUI:
Draw conclusions
The value of the stalls counter indicates how many cycles were spent waiting for input. This is a measure of idle time. If the percentage of total time that is spent stalling is higher than 5% of total latency of a stage execution, then stalling can be a contributor to longer latency of the application, and warrants investigation.