On using perf

perf.md

Setup

Avoid annoying security settings:

sudo sh -c 'echo 0 >> /proc/sys/kernel/kptr_restrict'
sudo sh -c 'echo 0 > /proc/sys/kernel/nmi_watchdog'
sudo sh -c 'echo -1 > /proc/sys/kernel/perf_event_paranoid'
echo 1 | sudo tee /proc/sys/kernel/sched_schedstats

Invoke

• RUSTFLAGS=-g perf record --call-graph dwarf cargo bench ...
• perf record -p <PID>

CPU utilization is lower than expected?

• sudo perf record -e sched:sched_stat_sleep -e sched:sched_switch -e sched:sched_process_exit -g -o ~/perf.data.raw ./a.out

Analyze

• Use Hotspot for correct/fast symbol demangling