path: root/testsuites/rhealstone/rhilatency/rhilatency.adoc

= Interrupt Latency Benchmark

This benchmark measures the time between the CPU's receipt of an interrupt
request and the execution of the first intruction in that interrupt service
routine.

== Directives

  * Intall_tm27_vector
  * Cause_tm27_intr


== Methodology

This benchmark takes advantage of the existing tm27 test support implemented
by most BSP's to achieve as much hardware independence as possible. Most BSPs
have an instruction to install an interrupt vector, and then provide code for
the ISR. rtems/testsuites/tmtests/tm27 uses this to test a variety of interrupt
related concepts. The benchmark is simple, the vector is installed, the time
is started, the interrupt is caused, and the time is ended in the first
instruction of the ISR. This is the only Rhealstone that is not an average.