Provided by: rt-tests_1.0-3_amd64 bug


       pi_stress - a stress test for POSIX Priority Inheritance mutexes


       pi_stress   [-i|--inversions   inversions]  [-t|--duration  seconds]  [-g|--groups  groups
       [-d|--debug]  [-v|--verbose]   [-s|--signal]   [-r|--rr]   [-p|--prompt]   [-m|--mlockall]
       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.

       -t n|--duration=n
              Run the test for n seconds and then terminate.

       -g n|--groups=n
              The number of inversion groups to run. Defaults to 10.

              Run in debug mode; lots of extra prints

              Run with verbose messages

              Terminate on receipt of SIGTERM (Ctrl-C). Default is to terminate on any keypress.

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

              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

              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 <>

                                           Nov 27, 2006                              pi_stress(8)