London Timing

[timbeiko]

Given that the difficulty bomb is expected to go off sometime in July, we will want London to hit mainnet then.

If we want a reasonable delay between picking blocks, going live on testnets, and going live on mainnet, this means we need to roughly follow the following timeline:

• July: Mainnet
• June: Testnets
• May: Blocks chosen, London testing done
• April: Select final EIPs + Reference Testing + Wrap up ephemeral network testing
• March: Select initial EIPs + Start ephemeral network testing

In other words, given we are already late-February, we should start thinking about what we want to see included in the London YOLO-nets (along with the difficulty bomb pushback (see EIP-3238)) if we want to not be rushed in implementation and deployment. This will be a bit of a change from our current process, as we'll need to start working on London before Berlin is live.

[q9f]

Timeline LGTM but who ensures we stick to it?

Also, we might want to do testnets as soon as possible rather than waiting till May to choose blocks.

[timbeiko]

@q9f

Timeline LGTM but who ensures we stick to it?

In this case, the difficulty bomb 😅 I do think agreeing to it now makes it easier to have hard deadlines (ex: no more new EIPs past X), which was an issue with Berlin, where we debated the pros/cons of various approaches for months.

Also, we might want to do testnets as soon as possible rather than waiting till May to choose blocks.

Good point, but that needs we need to have a final selection of EIPs and testing done even sooner.

[q9f]

no more new EIPs past X

that's what we did for Istanbul and apparently that worked out fairly well, a feature freeze at a given deadline and after that only implementation/testing of accepted/reviewed proposals. everything after that deadline simply goes into the next fork (Shanghai?)

[timbeiko]

Yep, that's what I'd go for @q9f. I think we need to select the "large" EIPs in March, have a "soft close" then, and at the latest add any "small" EIP in April, and everything else gets pushed to Shanghai (assuming they are still the highest priority when that fork comes).

[q9f]

commit to a feature freeze early (now) and communicate it right away

[jochem-brouwer]

I'd like to raise the point that if we go for this planning, we essentially end up having to plan two HFs in parallel (also Berlin #248). This is uncovered ground. This would also imply that (assuming that the scheduled Berlin HF time is accepted) we would have a gap of about 2.5 months between the two forks. This is very little time. In the past, we have seen that, due to circumstances, we usually end up delaying these HFs. I'd therefore say that this planning is very optimistic.

I'm a bit afraid that in practice, this is going to happen:

(1) We schedule Berlin around the time when the difficulty bomb kicks in (I also consider 2.5 months before it "around" this time).
(2) Due to parallel HF planning, we end up that London gets delayed a lot (assuming London has additional EIPs besides the difficulty bomb delay which is likely to be in this HF). Due to the difficulty bomb kicking in, we end up that London would be a MuirGlacier-like fork (only delay the bomb), which would be unfortunate.

[q9f]

In that case we should have the difficulty bomb delay in Berlin and relax the schedule for London a bit.

[timbeiko]

Proposed another schedule for Berlin which would give us a bit more slack, see #248 (comment)

[CryptoBlockchainTechnologies]

I'd like to raise the point that if we go for this planning, we essentially end up having to plan two HFs in parallel (also Berlin #248). This is uncovered ground. This would also imply that (assuming that the scheduled Berlin HF time is accepted) we would have a gap of about 2.5 months between the two forks. This is very little time. In the past, we have seen that, due to circumstances, we usually end up delaying these HFs. I'd therefore say that this planning is very optimistic.

I'm a bit afraid that in practice, this is going to happen:

(1) We schedule Berlin around the time when the difficulty bomb kicks in (I also consider 2.5 months before it "around" this time).
(2) Due to parallel HF planning, we end up that London gets delayed a lot (assuming London has additional EIPs besides the difficulty bomb delay which is likely to be in this HF). Due to the difficulty bomb kicking in, we end up that London would be a MuirGlacier-like fork (only delay the bomb), which would be unfortunate.

I agree to focus on Berlin and combine it with difficulty bomb reset

[timbeiko]

@CryptoBlockchainTechnologies it was decided on the call that Berlin's EIP list is final and the difficulty bomb will be pushed back this summer.

[holgerd77]

As with Berlin, I think it would be valuable to keep this issue open until past-London.