This test program tests the features of task isolation.

- Makes sure enabling task isolation fails if you are unaffinitized 
  or on a non-task-isolation cpu.

- Tests that /sys/devices/system/cpu/task_isolation works correctly.

- Validates that various synchronous exceptions are fatal in isolation
  mode:

  * Page fault
  * System call
  * TLB invalidation from another thread [1]
  * Unaligned access [2]

- Tests that taking a user-defined signal for the above faults works.

- Tests that isolation in "no signal" mode works as expected: you can
  perform multiple system calls without a signal, and if another
  process bumps you, you return to userspace without any extra jitter.

[1] TLB invalidations do not cause IPIs on some platforms, e.g. arm64
[2] Unaligned access only causes exceptions on some platforms, e.g. tile


You must be running under a kernel configured with TASK_ISOLATION;
this is available from the "dataplane" branch at:

http://git.kernel.org/cgit/linux/kernel/git/cmetcalf/linux-tile.git/

You must either have configured with TASK_ISOLATION_ALL or else
booted with an argument like "task_isolation=1-15" to enable some
task-isolation cores.  If you get interrupts, you can also add
the boot argument "task_isolation_debug" to learn more.

In addition, you must apply the one-line patch in
sched-tick-disable-hack.patch to disable the 1 Hz default tick.


To compile the test program, run "make".

Run the program as "./isolation" and if you want to run the
jitter-detection loop for longer than 10 giga-cycles, specify the
number of giga-cycles to run it for as a command-line argument.


Please send questions and comments to cmetcalf@kernel.org.