Scheduler latency analysis

Record context switches then show per-task wakeup latency; find runqueue starvation

perf sched record -- sleep 10 && perf sched latency --sort max
tool
perf17 commands
tags
perfperformancekerneltroubleshooting

More perf commands

  • Syscall trace via perf
    perf trace -s -p <pid>

    strace-like syscall trace with -s summary; lower overhead, no ptrace stop-the-world

  • Dynamic probe on function
    perf probe --add 'tcp_sendmsg size' && perf record -e probe:tcp_sendmsg -a -- sleep 5

    Add a kprobe with an argument, then record it; inspect kernel internals without rebuilding

  • Record CPU cycles
    perf record -g ./my_app

    Record performance data with call-graph info

  • Show perf report
    perf report

    Interactive display of recorded perf data

  • List available events
    perf list

    List all supported perf events on current system

all 17 perf commands