The story, "As I Was Saying" is non-fiction.
Now that we have the genre, lets find a sub-genre:
To find the sub-genre we will analyze the text, "Mr. Gluten writes the story of his humble origins". This means it is about HIM, not someone else. Therefore, it is an autobiography, because he is writing the story of his origins. If this is not the case, then it is a narrative.