Optimize Validator Pipeline

[vyzo]

Our validation pipeline is asynchronous: it spawns a goroutine for each incoming message, which may then get throttled based on topic and global limit throttles.
This creates a performance problem for message signature validation (#97) as we now have to enter the validation pipeline for every message when using signing (planned to become the default in ipfs and filecoin).

Proposed action:

• pre-spawn NUMCPU goroutines to handle the validation front-end.
• all signatures should be validated in the validation front-end goroutines
• create a distinction between synchronous and asynchronous validators (which may block and be otherwise slow due to network effects), such that:
  • synchronous validators are applied in the validation front-end
  • asynchronous validators are handled in a freshly spawned goroutine, limited by the throttles.

[aarshkshah1992]

@vyzo I would like to work on this. Is this up for grabs ? Have read the go-libp2p pubsub code and am looking for ways to contribute. This looks like a great first task !

[vyzo]

this is a relatively tricky issue to tackle for starting project -- and we are also not sure yet whether it is a problem.