How does scheduling work in xCORE and what is the priority of the each core?
Posted: Wed Sep 18, 2013 11:55 am
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The answer depend on whether you use an XS1 processor or an XS2 processor
(xCORE-200).
In both architectures, scheduling is a simple round robin process with each
active thread being executed in the next system clock cycle. This gives the
appearance of up to eight concurrent cores per xCORE tile. All cores are
independent and have equal priority meaning that each task always receives
a guaranteed minimum number of MIPS; this is central to building
deterministic and responsive systems.
In xCORE-200 processors you can declare that specific logical cores should have
high priority. High priority logical cores will get a slot when
they need a slot. However, low priority logical cores are
guaranteed to progress. When no more than four high priority logical cores
are used, they will each be guaranteed a minimum of one
fifth of the total throughput of the XCORE, and all remaining logical cores
will share the other one-fifth of the XCORE.