Who's been sleeping?
The better question is "Who's not been sleeping in the play Macbeth?"
The answer is the Macbeths.
In Act II, after they murder Duncan in his sleep, they begin to hear haunting sounds:
LADY MACBETH: I heard the owl scream and the crickets cry.
Later, Macbeth thinks he hears laughing and voices:
Both characters will have trouble sleeping for the rest of the play, such is there paranoia and guilt. In particular, Lady Macbeth will sleepwalk, continually washing her hands and repeating conversations she had that fateful night. The lack of sleep will drive her mad, to the point of suicide.
Your question is a bit vague, don't you think? (I'm using understatement.) Which play? Which act? Which scene? What novel, for that matter.
Somehow, your question has been categorized as belonging in the Macbeth group, so I'll answer it accordingly.
I assume you're asking about the Porter. He is apparently sleeping off a hangover when knocking on the door of Macbeth's castle wakes him. We see him on stage moving very slowly and in no hurry to answer the door. He eventually answers it.
The scene serves as comic relief between the assassination of Duncan and the discovery of the body.