Installing a test tool

Before we can convert our BeagleBone Black to a blazing real-time wonder, we need a way to measure latency in the Linux kernel. A popular tool for this purpose is cyclictest. Cylictest measures the amount of time that passes between when a timer expires and when the thread that set the timer actually runs. It uses time snapshots, one just before a specific time interval (t1), then another one just after the timer finishes (t2). We can then compare these two snapshot values to pinpoint excessive latency sources within the kernel.

Getting ready

The usual minimal setup is all you need: a BBB powered over mini USB with Internet connectivity enabled.

How to do it...

Cyclictest isn't available as a prebuilt binary. So, we will have to compile it from source:

1. Log in as root:

   # sudo -i
   

2. Go get the source files for cyclictest:

   # git clone git://git.kernel.org/pub/scm/linux/kernel/git/clrkwllms/rt-tests.git
   

3. Navigate to the new directory that git creates:

   # cd rt-tests
   

4. Compile that...