Hi Tiago,
I'm thinking that this alternative may suffer from the same problem as before if Genode's time clock becomes inconsistent whenever Linux is being executed in NW.
Do you know any other way to benchmark a world switch + processing + world switch scenario? Is there any timer I can execute inside TZ_VMM?
have you considered the use of a performance counter for measuring low-level code paths? For reference, you may take a look at the 'timestamp' function for ARM:
https://github.com/genodelabs/genode/blob/master/repos/os/include/spec/arm_v...
Compared to the other time sources, the counter is precise while having very little overhead. The exact meaning of the counter value may depend on the platform. E.g., on the Raspberry Pi where I used it, the counter increases every 64 clock cycles.
As far as I know, the feature must be explicitly enabled by adding the following line to your <build-dir>/etc/specs.conf:
SPECS += perf_counter
Be aware that further (TZ configuration) steps may be required to expose the counter to the normal world.
Cheers Norman