Cyclictest is part of the rt-tests package and is included in ost-devel images.

The following command is executed for each core:

cat /dev/zero > /dev/null

This causes 100% CPU utilization. Then cyclictest is invoked using the following command, to run for 24h:

sudo ./cyclictest -n -Sp80 -l86400000000 -i1000 -h1000 -q > histogramm.log

-l specifies the test duration in µs; 24h*60min/h*60min/s*1000ms/s*1000us/ms = 86'400'000'000us.

For more information about the flags, see Cyclictest.