title: Tally Backtraces for Inter-Processor Interrupt (IPI)
name: scf.stp
version: 1.0
author: William Cohen
keywords: interrupt backtrace
subsystem: kernel
status: production
exit: user-controlled
output: sorted-list
scope: system-wide
description: The Linux kernel function smp_call_function causes expensive inter-processor interrupts (IPIs). The scf.stp script tallies the processes and backtraces causing the interprocessor interrupts to identify the cause of the expensive IPI. On exit the script prints the tallies in descending frequency.
test_check: stap -p4 scf.stp
test_installcheck: stap scf.stp -c "sleep 0.2"