rtel wrote on Friday, January 23, 2015:
There are no such documents, as to publish such a thing would breach
license terms of FreeRTOS (and some other OSes).
There are lots of reasons for that:
There is no real way of directly comparing one with the other as the
API functions will do slightly different things.
Comparisons are always inaccurate and lead to bad feeling and
arguments in the community.
Metrics published by industry insiders are always skewed.
To benchmark a system you have a very deep understanding of the
system (how to tune it, for example in FreeRTOS turn off asserts, turn
of stack overflow checking, select the most appropriate function [task
notifications instead of semaphores], etc., etc.) and you cannot have
that level of understanding of all the systems you are benchmarking.
The fact you are looking for something that compares FreeRTOS with
RTLinux already shows you are wanting to compare products of massively
different scale that are designed to achieve different goals.
You cannot benchmark robustness, support quality, ease of use or
documentation standards, etc.
Different systems are designed with different goals. For example
benchmarking something designed to be as small as possible, or as
portable as possible, or as fast as possible, then making comparisons
between all of them makes little sense.
Some RTOSes have two steps to achieve what another can do in one.
Most people who ask for statistics don’t know what performance they
actually need in the first place, so are going around things backwards
as even the slowest fattest system might be the best choice for them if
it is fast ‘enough’ and thin ‘enough’ and it gets their part to market
You can always make something faster by removing functionality. Do
you want to have something ultra fast that doesn’t do anything?
Need I go on ;o)
FreeRTOS is free to download and use - create a scenario that is similar
to what your application is actually going to do to see if FreeRTOS
meets your requirements. If it does, great, use it, its not going to
cost you anything or earn us anything. If it doesn’t meet your needs
then also great - you learned that quickly and can move onto find