plot-nr-running
Create heat map and find imbalances from recorded sched_update_nr_running events with trace-cmd.
This script reads output of trace-cmd report
command with sched_update_nr_running
events. From this data it plots heat map showing number of active tasks on each core of processor with line graph showing imbalance between the numbers.
Usage
Check support of the sched_update_nr_running
event in the installed kernel:
trace-cmd list | grep sched_update_nr_running
Generate trace report with sched_update_nr_running
events:
trace-cmd record -e sched:sched_update_nr_running # append a command to trace or terminate with Ctrl+C
trace-cmd report > trace_report.trace
Create heat map with plot-nr-running.py
:
./plot-nr-running.py trace_report.trace
Arguments
The report file can be specified as positional argument, or passed through stdin
:
./plot-nr-running.py trace_report.trace
trace-cmd report | ./plot-nr-running.py
Other optional arguments can be viewed using --help
arguments:
--sampling SAMPLING Sampling of plotted data to reduce drawing point_time
--threshold THRESHOLD
Minimal difference of process count considered as
imbalance
--duration DURATION Minimal duration of imbalance worth reporting
--image-file IMAGE_FILE
Save plotted heatmap to file instead of showing
--lscpu-file LSCPU_FILE
File with output of lscpu from observed machine
Example
./plot-nr-running.py --lscpu-file example/lscpu.txt --image-file NAS_48_threads_group_imbalance_bug.png NAS_48_threads_group_imbalance_bug.trace.xz