howToUseCallgrind.txt

Mini Guide for myself on doing performance analytics

# Start the server with valgrind
valgrind --tool=callgrind ./nimstoryfont
## Do a couble things, end it with Ctrl + C to write data
# start KCachegrind and open the corresponding file

## Some other visualizations as suggested by SO:
./gprof2dot.py --format=callgrind --output=out.dot /path/to/callgrind.out
dot -Tpng out.dot -o graph.png



## For Flamegraphs
# Do a prod compile
nimble release
# Start a process
./nimstoryfont
# The second number is the PID, that's what you want
ps aux | grep ./nimstoryfont
# Record the data
sudo perf record -a -F 99 -g -p <PID>
## Do a thing that gets recorded, then do CTRL+C to stop
## Wait for perf to write its output in perf.data

# Turn the binary data in perf.data into "readable" data via perf.script
# Turn that into a flamegraph via the flamegraph gitrepo
sudo perf script | \
~/dev/FlameGraph/stackcollapse-perf.pl perf.script | \
~/dev/FlameGraph/flamegraph.pl > flamegraph.svg

TODO: This creates a so far useless flamegraph for the most part.
See how to make that useful