title: Generating Backtraces of Threads Waiting for IO Operations
name: sleepingBeauties.stp
version: 1.0
author: anonymous
keywords: io scheduler
subsystem: scheduler
status: production
exit: user-controlled
output: trace
scope: system-wide
description: The script monitor time threads spend waiting for IO operations (in "D" state) in the wait_for_completion function. If a thread spends over 10ms wall-clock time waiting, information is printed out describing the thread number and executable name. When slow the wait_for_completion function complete, backtraces for the long duration calls are printed out.
test_check: stap -p4 sleepingBeauties.stp
test_installcheck: stap sleepingBeauties.stp -c "sleep 1"