pi_stress - Man Page

a stress test for POSIX Priority Inheritance mutexes


pi_stress [-i|--inversions inversions] [-g|--groups groups [-d|--debug] [-v|--verbose] [-s|--sched sched_opts] [-r|--rr] [-p|--prompt] [-m|--mlockall] [-u|--uniprocessor]
pi_stress -h|--help


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.


-i n|--inversions=n

Run for n number of inversion conditions. This is the total number of inversions for all inversion groups. Default is -1 for infinite.

-g n|--groups=n

The number of inversion groups to run. Defaults to 10.


Run in debug mode; lots of extra prints

-D, ā€‰--duration=TIME

Specify a length for the test run.
Append 'm', 'h', or 'd' to specify minutes, hours or days.


Run with verbose messages


Run inversion group threads as SCHED_RR (round-robin). The default is to run the inversion threads as SCHED_FIFO.


scheduling options per thread type: id=[high|med|low],policy=[fifo,rr],priority=<n>,policy=deadline,runtime=<n>,deadline=<n>,period=<n>


Prompt before actually starting the stress test


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.


Call mlockall to lock current and future memory allocations and prevent being paged out


Display a short help message and options.


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.


No documented bugs.


Clark Williams <williams@redhat.com>


Nov 27, 2006 Linux System Administrator's Manual