We have a project in which the SOC has multi-core like ARM Cortex-R8; so we want an open-source RTOS that supports SMP scheduling. But it seems that no RTOS supports SMP, at least from its official release version.
Could anyone give the suggestion about it?
It is neither true that no RTOS has SMP support, or even that no open-source RTOS has support.
The open-source eCOS supports SMP (Symmetric Multiprocessing). http://ecos.sourceware.org/docs-3.0/ref/kernel-smp.html
Also NuttX http://nuttx.org/doku.php?id=wiki:nxinternal:smp
In the non open-source world, choices are wider, such as QNX Neutrino, and VxWorks.