Have the SW event device conform to the service core convention, where
-EAGAIN is return in case no work was performed.
Prior to this patch, for an idle SW event device, a service lcore load
estimate based on RTE_SERVICE_ATTR_CYCLES would suggest 48% core
load.
At 7% of its maximum capacity, the SW event device needs about 15% of
the available CPU cycles* to perform its duties, but
RTE_SERVICE_ATTR_CYCLES would suggest the SW service used 48% of the
service core.
After this change, load deduced from RTE_SERVICE_ATTR_CYCLES will only
be a minor overestimation of the actual cycles used.
* The SW scheduler becomes more efficient at higher loads.
Signed-off-by: Mattias Rönnblom <mattias.ronnblom@ericsson.com>
Acked-by: Morten Brørup <mb@smartsharesystems.com>
Acked-by: Harry van Haaren <harry.van.haaren@intel.com>
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