Debug

Debugging of real time outliers

In case test runs indicate outliers or unusual round-trip times in the statistics, Linux ftrace can be used to find the root cause. This can be done like this:

# Start tracing
trace-cmd start -e sched -e syscalls -e irq

# Set DebugStopTraceOnOutlier to True in reference.yaml or mirror.yaml configuration file

# Start reference and mirror as usual

# The reference application will stop after a round-trip time outlier is hit and will output an
# information message about it

# The mirror application will stop after a oneway time outlier is hit and will output an
# information message about it

# Get the trace
trace-cmd extract -a

# Copy trace.dat to development machine

# Analyze trace.dat with kernelshark or tracecompass to find the issue