title: Show reasons and durations for processes sleeping
name: latencytap.stp
version: 1.0
author: William Cohen
keywords: profiling
subsystem: kernel
status: experimental
exit: user-controlled
output: sorted-list
scope: system-wide
description: The latencytap.stp script collects data on the intervals processes are deactivated (sleeping).  The script categorizes the reasons for the sleeps by analyzing the backtraces and displays a sorted list of the top 20 causes from largest total sum time sleeping to smallest. The output is updated every 30 seconds. The script needs to be compiled with the '--all-modules' option to produce reasons for sleeps caused by modules.  Optionally, this script can be used with the '-c' or '-x' options to focus on a specific PID.
test_check: stap -p4 --all-modules latencytap.stp
test_installcheck: stap latencytap.stp --all-modules -c "sleep 0.2"