Greenfield surveys credit the next day - mine usually come in around lunch time. You'll probably see credit in a few hours. Since it's Friday, you won't see credit for the Greenfield you took today until Monday. Greenfield only credits on business days. All other surveys credit within a few hours :)
If you haven't already seen this thread,
check this one out from the Member Q&A forum. jnorth explains how surveys track in post #3. I've been a member for a while, but her post helped me to understand more how surveys work, so it could be helpful to you too!