Hi, "David Bonnell" <dave@xxxxxxxxxxxxxxx> writes: > If each thread obtains an (exclusive) lock on the pixel region then > the tasks will effectively be serialized and overall execution time > will increase compared to a non-threaded implementation due to the > threading overheads. (Queue manipulation, thread creation and > context switching, etc). Please read my description again; I don't think it was that bad. Of course there's no exclusive lock on the pixel region while it is being processed. Sven