Hello Dear L4 Hackers,
I am still writing on my bachelors-thesis on the performance of L4/Fiasco and wanted to ask you
if you can give me some hints and ideas. My goal was to find out how the time-costs are divided between ipc, memory access and scheduling
and resulting out of this what properties programs should have that makes them execute as fast as possible.
For measuring the ipc-time i used the ipc_example.c-file in the ./src/l4/pkg/examples/sys directory and added rdtsc (Read Time Stamp Counter)-instructions
before and after making the ipc-call and then calculating the difference between the two values. This was executed in a loop and the resulting values were divided into
ten equal-sized range-classes depicting them as a histogram.The results showed the ipc-time to be pretty stable with almost all values falling into one class
(Sorry for my shitty Englisch anyway).
Does anyone have an idea what kind of measurement one could do for a measurement of the scheduling? I found the function l4_scheduler_idle_time (...), but I don't
have an idea for using it in a concrete program or experiment setup.
I also thought about repeatedly measuring the time it takes for one context-switch, but I don't know in which place exactly I would have to insert the rdtsc-instructions.
Does anyone know which exact C-file would have to be modified for that?
I am thankful for any answer,
regards,
the Steppenwolf