Performance of L4

Patrick Staeblein patrick.staeblein at
Fri Dec 25 19:43:13 CET 2015

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). 

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

Does anyone know which exact C-file would have to
be modified for that? 

I am thankful for any answer, 


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