What doed "staged work underrun" mean? Thanks in advance

[DMac66]

Thx

[ScripterRon]

The miner prepares work in advance so that it is ready to go when a hash operation is completed for the current work unit.  The message you see occurs when there is not enough work available when it is needed.  There is often a miner configuration parameter to set the size of this queue.  Some miners (such as BFGMiner) will automatically increase the amount of queued work when this happens.

It is a balancing act because the miner doesn't want to request too much work in advance since that can increase the number of stale shares.  But you want to request enough to keep the mining operation going without delays.