make latency measurement a moving average

[jbenet]

dht keeps Peer's latency, but right now it's only the last value. this should probably be an EWMA.

[btc]

+1 for EWMA

Whatcha think of this?

https://godoc.org/github.com/rcrowley/go-metrics#EWMA

https://github.com/rcrowley/go-metrics

[whyrusleeping]

Yeap, Agreed.

[jbenet]

Looks like go-metrics EWMA counts number of events, not value averages: https://github.com/rcrowley/go-metrics/blob/3be59ceb5538550555459fb77d0efe0e218cdfc7/ewma.go#L79-L118 Am i looking at this wrong?

[mappum]

Using a library is probably overkill, to implement it you simply need to do:

const w float32 = 0.6 // set a weight for how fast the average changes

...

ping := peer.Ping() // get the current latency
avgPing = ping*w + avgPing*(1-w) // update EWMA

So if our w is set to 0.75, our average is at 100ms, then we send a new ping and get 50ms, the average will update to 87.5ms.

[whyrusleeping]

@mappum +1

[jbenet]

Using a library is probably overkill

Modularity!!!

you simply need to do

But you're right, no need to use a library as bloated as that. Maybe implement it in one small package.

all of this will get easier once ipfs can be a package manager for go code

[whyrusleeping]

@jbenet where do you get all of these images?

[mappum]

That's @substack's avatar

[jbenet]

I think this is done already.