Real-time task latency in general-purpose hypervisors - testing the limits

Emulating a RT task and measuring the response latency of its thread by means of the high-resolution testing tool Cyclictest. The thread was clocked at 10ms, and a FIFO scheduling policy was used, with the thread being assigned the highest priority. Measurements were performed in distinct testing environments, some of which had best effort concurrent threads competing for the machine resources. For this purpose, the workload generator tool stress was used. A total of 20 simultaneous workers were instantiated (10 exercising the CPU by spinning on square root function, and 10 spinning on malloc/free operations with 64 MB blocks), which was enough to overload the available cores. Each test had a duration of 8 hours, which led to over 2.5 million samples per test.The underlying hardware consisted of an Asus PRIME H410M-A motherboard, with an Intel® Core™ i5-10400F 2.9GHz CPU with 6 cores, and 16GB DDR4 RAM running at 2666MHz.