On 11/10/2018 17:32, Thawra Kadeed wrote:
Thanks a lot Sebastian for your answer.
Actually, we are planning to run a multi-core system using a
network-on-chip and network interfaces as a physical interconnect
between cores instead of the bus interconnect. I understood that MPCI
by the OS maybe stay the same even if we change the RTEMS version. Is
that right?
Probably yes, but I guess the MPCI support is not in wide spread use
currently. It will be definitely easier if you use the same RTEMS
version on all nodes. One option would be to use RTEMS SMP instead.
On the other hand, I was looking for a very old version of RTEMS and I
found in this site "https://git.rtems.org/rtems/tag/?h=3.5.1"; a
version from 1996
which is really lightweight. However, I have not seen any support for
ARM cortex A architecture.
The ARM Cortex-A didn't exist in 1996.
The issue is actually that the current version of RTEMS is hard to
predict and analyze because it supports many features to provide high
performance like POSIX and others. in the real-time part, we need very
lightweight RTEMS excluding all other features where the RTEMS kernel
does not exceed 1 MB.
So what do you recommend us? could we use the current version
excluding all other advantages from the RTEMs kernel where we minimize
the kernel as much as possible?
RTEMS is a library and it was designed so that only parts needed by the
application end up in the executable. This improved over time, so RTEMS
5 is probably the best RTEMS in terms of modularity. RTEMS 5 supports
transitive priority inheritance. This makes it a bit more complex
compared to earlier RTEMS versions. It would be possible to bring back
the simplified priority inheritance support if there is a real need for
this.
If your limit is 1MiB, this all doesn't matter. This is more than enough
for the operating system core. If you need the new network stack
(libbsd), then you may need more (about 2MiB).
--
Sebastian Huber, embedded brains GmbH
Address : Dornierstr. 4, D-82178 Puchheim, Germany
Phone : +49 89 189 47 41-16
Fax : +49 89 189 47 41-09
E-Mail :sebastian.hu...@embedded-brains.de
PGP : Public key available on request.
Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
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