Good day!
I came across the sentence "The hall was empty, servants having long gone home or sleeping in their quarters" and what bothers me here is "servants having long home"

I'd say "the hall was empty, servants have long gone home".

I see it as a perfect form of gerund, but isn't it supposed to describe some action? Like "Servants having long gone home left the hall empty". The way it's been used in the original sentence just leaves it to be uncomplete.

Do I miss something about usage of perfect gerund? Would it sound natural to use "servants have gone home"?

Question

Good day!
I came across the sentence "The hall was empty, servants having long gone home or sleeping in their quarters" and what bothers me here is "servants having long home"

I'd say "the hall was empty, servants have long gone home".

I see it as a perfect form of gerund, but isn't it supposed to describe some action? Like "Servants having long gone home left the hall empty". The way it's been used in the original sentence just leaves it to be uncomplete.

Do I miss something about usage of perfect gerund? Would it sound natural to use "servants have gone home"?

Answer

This is a participle rather than a gerund.

'having long gone home' means 'because the servants had long gone home'

Without using a participle clause, it would be:

"The hall was empty because the servants had long gone home or were sleeping in their quarters"

You should do a web search for 'relative and participle clauses' if you'd like to learn more about it.

It's a difficult topic but it's very interestiing)

Answer

The original sentence is ok as the use of gerund is for phrases. As I am not an English teacher, I am not sure about the exact grammar point. 
If you wish to change it, it will be:
.... servants have long gone home or are  sleeping in their quarters ....