Add option to have multiple network processing thread

[asdacap]

• Currently the network thread is essentially single threaded with some request spawning other task.
• This add an option to allow setting more than 1 thread.
• On faster internet (> 500Mbps), this becaomes a bottleneck on old blocks.
• However, the threads kinda acts as a throttling mechanism which prevent external request from affecting block processing.

Changes

• Add option to set more than 1 network thread.
• Add tests to make sure frame encoder/decoder can run in parallel of each other.

Types of changes

What types of changes does your code introduce?

• New feature (a non-breaking change that adds functionality)
• Optimization

Testing

Requires testing

• Yes
• No

If yes, did you write tests?

• Yes
• No

Notes on testing

Optional. Remove if not applicable.

Remarks

Optional. Remove if not applicable.

[LukaszRozmej]

Would Networking be faster if for blocks and receipts we wouldn't do a full deserialization and allocating memory, but instead use something like ReceiptsIterator (and implement BlockIterator) for that and then dump the bytes directly to DB? This could save CPU cycles, allocations, GC ect.

[LukaszRozmej]

should there be a check that if it is 1 it would spawn SingleThreadEventLoop ? Maybe it is more optimized than MultithreadEventLoopGroup(1)?

[asdacap]

For blocks, at least during sync, the main bottleneck is likely IO. I guess, going straight to db would reduce some CPU, but I suspect its not going to change much. For receipts, the main bottleneck is the receipt verification. I tried a custom task scheduler before and it can saturate the whole CPU suggesting some scheduling inefficiency. I doubt other part is significant.

[LukaszRozmej]

For blocks, at least during sync, the main bottleneck is likely IO. I guess, going straight to db would reduce some CPU, but I suspect its not going to change much. For receipts, the main bottleneck is the receipt verification. I tried a custom task scheduler before and it can saturate the whole CPU suggesting some scheduling inefficiency. I doubt other part is significant.

as receipt thing is available I will try doing it some time.