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╔══════════════════════════════════════════════════════════════════════╗
║ ETHEREUM IMPROVEMENT PROPOSAL 8198 ║
║ Variable Slot Timing Infrastructure & Slot Duration Reduction ║
╚══════════════════════════════════════════════════════════════════════╝
,/ ──────────────────
,'/ / $ $ $ $ $ $ \
,' / ┌────────────────────────┐ O
,' /_____, │ QUICK SLOTS │ ║
.'____ ,' │ ╔══════╤══════╤══════╗ │ ║
/ ,' │ ║ 8 │ 8 │ 8 ║ │ ║
/ ,' │ ╚══════╧══════╧══════╝ │===╝
/,' ├────────────────────────┤
/' └────────────────────────┘
SEC 01 ── ABSTRACT ════════════════════════════════════════════════════════════════════════
╔══════════════════════════════════════════════════════════════════════╗ ║ Make slot duration a runtime configuration. Then reduce it. ║ ╚══════════════════════════════════════════════════════════════════════╝
This EIP turns SLOT_DURATION_MS from a compile-time constant into a fork-activated runtime parameter on the consensus layer, then uses that infrastructure to reduce slot duration from 12 seconds to 8 seconds. Block gas limits and blob parameters scale proportionally to maintain constant throughput per unit time.
SEC 02 ── THE PROBLEM ════════════════════════════════════════════════════════════════════════
╔══════════════════════════════════════════════════════════════════════╗
║ Twelve seconds is slow.█ ║
╚══════════════════════════════════════════════════════════════════════╝
Slot time is the heartbeat of Ethereum's user experience. Every second shaved off means faster transaction landings, faster exchange deposits, and faster real-world payments. But the costs of long slots extend well beyond UX — they inflate arbitrage losses, widen the MEV extraction window, grant builders an exploitable free option on blocks, and force the ecosystem to build complex preconfirmation protocols to paper over the latency.
12s ├▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓┤ CURRENT: 12,000 ms
│ │ │
8s ├▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓┤ │ PROPOSED: 8,000 ms (-33%)
│ │ │
0s 8s 12s
12s ├░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░┤ 0 slots 8s ├░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░┤ 0 slots
WASTED: 0s
┌──────────────────┬────────────────┬────────────────┬─────────────────┐ │ │ CURRENT (12s) │ PROPOSED (8s) │ CHANGE │ ├──────────────────┼────────────────┼────────────────┼─────────────────┤ │ GAS / BLOCK │ 36,000,000 │ 24,000,000 │ -33% │ │ BLOBS / BLOCK │ 6 │ 4 │ -33% │ │ GAS / SECOND │ 1,500,000 │ 1,500,000 │ = UNCHANGED │ │ BLOBS / SECOND │ 0.5 │ 0.5 │ = UNCHANGED │ │ FINALITY │ ~13 min │ ~8.5 min │ -33% │ └──────────────────┴────────────────┴────────────────┴─────────────────┘
┌─ KEY INVARIANT ──────────────────────────────────────────────────────┐ │ │ │ Throughput per second is preserved. Gas-per-second and │ │ blobs-per-second remain constant — blocks get smaller │ │ but arrive faster. │ │ │ └──────────────────────────────────────────────────────────────────────┘
SEC 03 ── BENEFITS ════════════════════════════════════════════════════════════════════════
┌──────────────────┬────────────────────────────────┬──────────────────┐ │ DOMAIN │ EFFECT │ METRIC │ ├──────────────────┼────────────────────────────────┼──────────────────┤ │ │ │ │ │ User Experience │ Faster confirmations, exchange │ -33% latency │ │ │ deposits, and payments. │ │ │ │ │ │ │ DEX Pricing │ Arb losses scale with sqrt of │ ~18% reduction │ │ │ inter-block time. Tighter │ in arb losses │ │ │ on-chain pricing. │ │ │ │ │ │ │ MEV │ Compress surplus per block. │ Non-linear │ │ │ Squeezes the entire MEV │ compression │ │ │ supply chain. │ │ │ │ │ │ │ ePBS / Empty │ Builder's free option on the │ Reduced option │ │ Blocks │ block shrinks with slot │ value │ │ │ duration. │ │ │ │ │ │ │ Preconfirmations │ Attacks root cause of latency. │ Reduced │ │ │ Reduces need for extra trust │ complexity │ │ │ and protocol complexity. │ │ │ │ │ │ │ L2 Sequencing │ Based rollups inherit L1 block │ -33% L2 latency │ │ │ time. Faster L1 = faster L2s, │ │ │ │ zero changes needed. │ │ │ │ │ │ └──────────────────┴────────────────────────────────┴──────────────────┘
SEC 04 ── APPROACH ════════════════════════════════════════════════════════════════════════
Nobody knows the safe minimum slot duration with today's client implementations. Rather than stalling on the choice of a number, the work is separated into three phases.
┌───────────────────────┬───────────────────────┬──────────────────────┐ │ PHASE 1 │ PHASE 2 │ PHASE 3 │ │ INFRASTRUCTURE │ CHARACTERIZE │ REDUCE │ ├───────────────────────┼───────────────────────┼──────────────────────┤ │ │ │ │ │ Remove the 12-second │ Map CL bottlenecks │ Cut slot duration │ │ assumption. Make │ via devnets and │ based on empirical │ │ SLOT_DURATION_MS a │ benchmarks. Blob │ data. Fix client │ │ fork-activated │ propagation, attest │ constraints, reduce │ │ runtime config. │ aggregation, block │ further, iterate. │ │ │ building. │ │ │ │ │ │ │ [██░░░░░░░░░░░░░░░░] │ [░░░░░░░░░░░░░░░░░░] │ [░░░░░░░░░░░░░░░░░░] │ │ IN PROGRESS │ PENDING │ PENDING │ │ │ │ │ └───────────────────────┴───────────────────────┴──────────────────────┘
┌─ FALLBACK ───────────────────────────────────────────────────────────┐ │ │ │ Phase 1 has standalone value regardless of the final number. │ │ If analysis shows 12 seconds is optimal, the effort still │ │ delivers cleaner client architecture, a comprehensive CL │ │ performance characterization, and the readiness to reduce │ │ when conditions permit. │ │ │ └──────────────────────────────────────────────────────────────────────┘
SEC 05 ── SPECIFICATION ════════════════════════════════════════════════════════════════════════
At FORK_EPOCH, the following constants take effect. The general principle: do not adjust a constant unless there is a concrete security or economic failure from leaving it unchanged.
┌──────────────────────────────────┬────────────────┬──────────────────┐ │ PARAMETER │ CURRENT │ NEW │ ├──────────────────────────────────┼────────────────┼──────────────────┤ │ SLOT_DURATION_MS │ 12,000 │ 8,000 │ │ BASE_REWARD_FACTOR │ 64 │ 42 │ │ INACTIVITY_PENALTY_QUOTIENT │ 16,777,216 │ 37,748,736 │ │ MIN_EPOCHS_FOR_BLOB_SIDECARS │ 4,096 │ 6,144 │ │ CHURN_LIMIT_QUOTIENT │ 65,536 │ 98,304 │ └──────────────────────────────────┴────────────────┴──────────────────┘
Gas limit scales by new_slot_duration / old_slot_duration at the fork block. Normal gas limit voting resumes from the next block. Blob parameters scale proportionally via a new BLOB_SCHEDULE entry.