I speak of semaphore limits, not ram or cpu. Defaults on RPi are quite restrictive.
Thanks for the tip -- cat /proc/sys/kernel/sem showed: 250 32000 32 128
I've doubled it to 500 64000 32 256, so we'll see if that helps. Will let you know.
Well, thinking that was the solution I took a long break -- got back to see cgminer only ran 9 minutes before throwing the same sem_post/callback error
On restart, it ran a bit over 5 hours then same error. Spose it could be hardware -- will load up bfgminer to see if I have the same prob.