multigas: use unchecked add to improve performance#644
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multigas: use unchecked add to improve performance#644
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Replacing safe/saturating adds with unchecked ones can improve performance by up to ~19% in synthetic benchmarks. We can safely replace checked adds when we know that there isn't a chance of overflow. For instance, in the EVM.run() function, a uint64 gas value won't overflow because the program would run out of gas first. Here are some benchmark results of programs that * Without optmization: ``` $ go test -bench=BenchmarkSimpleLoop -benchtime=300x ./core/vm/runtime/ goos: linux goarch: amd64 pkg: github.com/ethereum/go-ethereum/core/vm/runtime cpu: AMD Ryzen 9 7900 12-Core Processor BenchmarkSimpleLoop/staticcall-identity-100M-24 300 351708000 ns/op 224673426 B/op 6164445 allocs/op BenchmarkSimpleLoop/call-identity-100M-24 300 423641326 ns/op 241626949 B/op 6711476 allocs/op BenchmarkSimpleLoop/loop-100M-24 300 205678035 ns/op 3858 B/op 42 allocs/op BenchmarkSimpleLoop/loop2-100M-24 300 220230885 ns/op 3859 B/op 42 allocs/op BenchmarkSimpleLoop/call-nonexist-100M-24 300 608773800 ns/op 149273581 B/op 3731316 allocs/op BenchmarkSimpleLoop/call-EOA-100M-24 300 412351029 ns/op 95533857 B/op 2985050 allocs/op BenchmarkSimpleLoop/call-reverting-100M-24 300 622313948 ns/op 412718387 B/op 5715753 allocs/op PASS ``` * With optmization: ``` $ go test -bench=BenchmarkSimpleLoop -benchtime=300x ./core/vm/runtime/ goos: linux goarch: amd64 pkg: github.com/ethereum/go-ethereum/core/vm/runtime cpu: AMD Ryzen 9 7900 12-Core Processor BenchmarkSimpleLoop/staticcall-identity-100M-24 300 337222851 ns/op 224673593 B/op 6164445 allocs/op BenchmarkSimpleLoop/call-identity-100M-24 300 403063559 ns/op 241626933 B/op 6711476 allocs/op BenchmarkSimpleLoop/loop-100M-24 300 183246194 ns/op 3859 B/op 42 allocs/op BenchmarkSimpleLoop/loop2-100M-24 300 203989420 ns/op 3858 B/op 42 allocs/op BenchmarkSimpleLoop/call-nonexist-100M-24 300 521509487 ns/op 149273509 B/op 3731316 allocs/op BenchmarkSimpleLoop/call-EOA-100M-24 300 333846242 ns/op 95533859 B/op 2985050 allocs/op BenchmarkSimpleLoop/call-reverting-100M-24 300 593545585 ns/op 412723111 B/op 5715769 allocs/op PASS ```
gligneul
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Pulls in OffchainLabs/go-ethereum#644 Close NIT-4668
gligneul
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MishkaRogachev and
eljobe
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eljobe
Decrement single gas and increase multi-gas in a single function, ensuring we don't make mistakes of incrementing multi-gas without checking for overflow.
These functions were made specificly for the interpreter, we probably don't want them to be used in other places.
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Everything looks correct, just some nitpicks
| if op == SELFDESTRUCT && cost == params.SelfdestructGasEIP150 { | ||
| usedMultiGas.SaturatingIncrementInto(multigas.ResourceKindComputation, params.WarmStorageReadCostEIP2929) | ||
| usedMultiGas.SaturatingIncrementInto(multigas.ResourceKindStorageAccessWrite, cost-params.WarmStorageReadCostEIP2929) | ||
| // It is safe to call UncheckedIncrementInto because because we checked single gas. |
| return ErrOutOfGas | ||
| } | ||
| c.Gas -= dynamicCost | ||
| // It is safe to call UncheckedAddInto because because we checked single gas. |
| return z, true | ||
| } | ||
|
|
||
| for i := 0; i < int(NumResourceKind); i++ { |
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Since you are editing this file anyway, maybe update all plain for loops here to range-based form: for i := range int(NumResourceKind)
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Replacing safe/saturating adds with unchecked ones can improve performance by up to ~19% in synthetic benchmarks. We can safely replace checked adds when we know that there isn't a chance of overflow. For instance, in the EVM.run() function, a uint64 gas value won't overflow because the program would run out of gas first.
Here are some benchmark results of programs that
Pulled in by OffchainLabs/nitro#4585