On 23 Mar 2015, at 11:13 , Reinier Millo Sánchez rmillo@uclv.cu wrote:

I want to use Fiasco.OC to construct real-time's systems. I want to do some benchmarks over Fiasco.OC, to measure the performance in different hardware platforms and compare the results with tests made to others solutions based maybe on Linux Kernel.

For now i want to test the real-time capabilities on some platforms, measuring some aspects of Fiasco.OC (in time or cycles):

• Execution mode switch (user-kernel)
• Thread/Context switch on the CPU
• Scheduler algorithm
• IPC Mechanism
• Thread/Task creation/destruction

Somebody have measured this elements in Fiasco.OC or can give me some ideas?

Measuring real-time performance is somewhere between hard and impossible.

The problem is that in order to make any real-time guarantees, you need a safe upper bound on the worst-case latencies. You can’t get those with measurements, you’re likely to under-estimate the WCET by orders of magnitude.

The only sound WCET analysis of a protected-mode OS I’m aware of is the one done on seL4, see - http://www.ssrg.nicta.com.au/publications/nictaabstracts/Blackham_SCRH_11.ab... - http://www.ssrg.nicta.com.au/publications/nictaabstracts/Blackham_SH_12.abst...

Gernot