pi_stress - Man Page
a stress test for POSIX Priority Inheritance mutexes
# SPDX-License-Identifier: GPL-2.0-or-later
Synopsis
pi_stress [-d|--debug] [-D|--duration [-g|--groups N] [-i|--inversions INV] [--json FILENAME] [-m|--mlockall] [-p|--prompt] [-q|--quiet] [-r|--rr] [-s|--sched OPTS] [-u|--uniprocessor] [-v|--verbose] [-V|--version]
Description
pi_stress is a program used to stress the priority-inheritance code paths for POSIX mutexes, in both the Linux kernel and the C library. It runs as a realtime-priority task and launches inversion machine thread groups. Each inversion group causes a priority inversion condition that will deadlock if priority inheritance doesn't work.
Options
- -d|--debug
Run in debug mode; lots of extra prints
- -D TIME, --duration=TIME
Specify a length for the test run.
Append 'm', 'h', or 'd' to specify minutes, hours or days.- -g N|--groups=N
The number of inversion groups to run. Defaults to 10.
- -h|--help
Display a short help message and options.
- -i N|--inversions=N
N number of inversion conditions. This is the total number of inversions for all inversion groups. Default is -1 for infinite.
- --json=FILENAME
Write final results into FILENAME , JSON formatted.
- -m|--mlockall
Call mlockall to lock current and future memory allocations and prevent being paged out
- -p|--prompt
Prompt before actually starting the stress test
- -q|--quiet
Suppress running output
- -r|--rr
Run inversion group threads as SCHED_RR (round-robin). The default is to run the inversion threads as SCHED_FIFO.
- -s OPTS|--sched OPTS
scheduling options per thread type:
id=[high|med|low],
policy=[fifo,rr],priority=N,
policy=deadline,runtime=N,deadline=N,period=N- -u|--uniprocessor
Run all threads on one processor. The default is to run all inversion group threads on one processor and the admin threads (reporting thread, keyboard reader, etc.) on a different processor.
- -v|--verbose
Run with verbose messages
- -V|--version
Print version number
Caveats
The pi_stress test threads run as SCHED_FIFO or SCHED_RR threads, which means that they can starve critical system threads. It is advisable to change the scheduling policy of critical system threads to be SCHED_FIFO prior to running pi_stress and use a priority of 10 or higher, to prevent those threads from being starved by the stress test.
Bugs
No documented bugs.
Author
Clark Williams <williams@redhat.com>