⚠️ Draft Standards Track: Core

EIP-7691: Blob throughput increase

Increase the number of blobs to reach a new target of x blobs per block, to be defined by performing tests.

Authors	Parithosh Jayanthi (@parithosh), Toni Wahrstätter (@nerolation), Sam Calder-Mason (@samcm), Andrew Davis (@savid)
Created	2024-04-17
Discussion Link	https://ethereum-magicians.org/t/eip-7691-blob-throughput-increase/19694

Abstract
Motivation
Specification
- Parameters
Rationale
- Simplicity
- Testable changes
Backwards Compatibility
Security Considerations
Copyright

Abstract

This EIP proposes to increase to the number of blobs in a block to provide more scale to Ethereum via L2 solution that rely on L1 data capacity.

Motivation

Ethereum, with its rollup centric roadmap, scales by relying on L2. Since the Dencun fork, the blob gas target and maximum was set to 3/6 respectively. The blob gas limit was arrived at based on a series of big block tests performed on the Ethereum mainnet network as well as a series of testnets. The values were chosen cautiously, as it’s extremely hard to predict the exact p2p behaviour of Ethereum mainnet.

As we now have the Dencun upgrade live, we are able to use monitoring tools to check the network health. Initial monitoring indicates that we have a stable network with the current gas target and the re-org rate is trending downwards. Additionally, analysis on messages in gossipsub indicate that the inclusion of IDONTWANT messages could bring us a significant bandwidth savings. This allows us to consider starting a series of big block and blob tests to determine the theoretical headroom we currently have. The EIP specifies a proposed new blob gas target and limit based on the series of tests.

Additional EIPs such as EIP-7623 proposes a calldata cost increase which would significantly lower the worst case base block size, thus creating more headroom for a potential blob throughput increase.

The current long term plan of Ethereum is to implement peerDAS as specified by EIP-7594, but given the uncertain timelines, this EIP aims to increase the throughput short term to provide some scaling until future solutions are deployed. In order to alleviate valid concerns about solo-stakers, approaches such as the inclusion of a flag indicating the max blobs per block for locally built blocks could be considered.

Specification

Parameters

Constant	Value
`PECTRA_FORK_EPOCH`	`tbd`
`MAX_BLOBS_PER_BLOCK`	`tbd`

Rationale

Simplicity

A blob limit increase at the fork transition is relatively straightforward from an implementation perspective. We would need to deploy an increased amount of monitoring around the fork epoch, but after a period of stability we can assume that the blob limit increase was successful, reducing any unexpected co-ordination efforts.

The EIP aims to minimize the amount of testing and implementation effort from the perspective of the client teams, to allow for more resources to be allocated to peerDAS and other scaling research.

While this EIP may not achieve the new optimal blob limit, it offers a compromise for a short term increase.

Testable changes

Through the use of big block/blob tests on Ethereum mainnet as well as testnets, we can earn a high degree of certainity that the blob limit increase would not negatively impact the network. These tests as well as the associated analysis can be performed mostly by non-client team entities, with minimal input required. Since the changes are quite contained, the EIP should be able to reduce the risk of the blob limit increase.

Backwards Compatibility

todo

Security Considerations