Hi Pratik, On Mon, Apr 12, 2021 at 12:43 AM Pratik Rajesh Sampat <psampat@xxxxxxxxxxxxx> wrote: > > The cpuidle latency selftest provides support to systematically extract, > analyse and present IPI and timer based wakeup latencies for each CPU > and each idle state available on the system. > > The selftest leverages test-cpuidle_latency module's debugfs interface > to interact and extract latency information from the kernel. > > The selftest inserts the module if already not inserted, disables all > the idle states and enables them one by one testing the following: > 1. Keeping source CPU constant, iterate through all the CPUS measuring > IPI latency for baseline (CPU is busy with cat /dev/random > /dev/null > workload) and then when the CPU is allowed to be at rest > 2. Iterating through all the CPUs, sending expected timer durations to > be equivalent to the residency of the deepest idle state enabled > and extracting the difference in time between the time of wakeup and > the expected timer duration > > The timer based test produces run to run variance on some intel based > systems that sport a mechansim "C-state pre-wake" which can > pre-wake a CPU from an idle state when timers are armed. For systems and > architectures that don't have this mechansim can leverage timer tests > with the -i option. > > To run this test specifically: > $ sudo make -C tools/testing/selftests TARGETS="cpuidle" run_tests > > There are a few optional arguments too that the script can take > [-h <help>] > [-i <run timer tests>] > [-m <location of the module>] > [-o <location of the output>] > [-v <verbose> (run on all cpus)] > Default Output location in: tools/testing/selftest/cpuidle/cpuidle.log > > To run the test without re-compiling: > $ cd tools/testing/selftest/cpuidle/ > $ sudo ./cpuidle.sh > > Signed-off-by: Pratik Rajesh Sampat <psampat@xxxxxxxxxxxxx> Reviewed-by: Doug Smythies <dsmythies@xxxxxxxxx> ...
