fix(gas): enforce maxFeePerGas >= maxPriorityFeePerGas (EIP-1559 invariant)#42
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…riant) gasFeeCap was set to 2x eth_gasPrice and only clamped up to 2x baseFee — never to the tip. On a quiet chain eth_gasPrice decays to the floor (~0.001 gwei), so the auto fee cap (~0.002 gwei) fell below the default 1 gwei tip, producing invalid EIP-1559 txs (maxFeePerGas < maxPriorityFeePerGas) that the node rejects outright (0 mined, pendingTxCount=0). Bistable: once blocks go empty, gasPrice stays low and every test fails until something lifts it. Clamp gasFeeCap up to gasTipCap before the existing 2x-baseFee guard. Verified: on a stuck chain (gasPrice 0.001 gwei, default 1 gwei tip), a direct 200 TPS run went from confirmed=0/failed=5874 to confirmed=1824/failed=0. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
mandrigin
approved these changes
Jun 25, 2026
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Bug
gasFeeCap(maxFeePerGas) is computed as2 × eth_gasPriceand clamped up to2 × baseFee— but never togasTipCap(maxPriorityFeePerGas). On a quiet chaineth_gasPricedecays to the floor (~0.001 gwei), so the auto fee cap (~0.002 gwei) falls below the default 1 gwei tip. That's an invalid EIP-1559 tx (maxFeePerGas < maxPriorityFeePerGas), which the node rejects at submission —pendingTxCount=0, nothing mined.It's bistable: while txs land paying a 1 gwei tip,
eth_gasPricestays high (valid); once blocks go empty,eth_gasPricedecays and every test fails until something lifts it.Fix
Clamp
gasFeeCapup togasTipCap(the EIP-1559 invariant) before the existing2×baseFeeguard, ininternal/loadgen/init.go.Verification
On a stuck local chain (
eth_gasPrice≈ 0.001 gwei, default 1 gwei tip):confirmed=0, failed=5874, on-chaintxCount=0confirmed=1824, failed=0, on-chaintxCount=1824(gasUsed 38.3M)🤖 Generated with Claude Code