Add multi dimensional multi constraint pricer algorithm #4012

MishkaRogachev · 2025-11-14T14:01:49Z

Fixes NIT-4069
(Temporary includes #3995)

Depends on:

core: Add multigas to EndTxHook and safeDecrement go-ethereum#579

Changes:

Implement multi-gas pricing constraints model
Modify AddToGasPool to accept multigas
Implement GasModelToUse to select a model depending on the configuration
Migrating gas constraints from single-dimensional to multi-dimensional model (open question)

github-actions · 2025-11-17T11:46:12Z

❌ 2 Tests Failed:

Tests completed	Failed	Passed	Skipped
2178	2	2176	0

View the top 2 failed tests by shortest run time

TestVersion30

Stack Traces | 6.090s run time

... [CONTENT TRUNCATED: Keeping last 20 lines]
INFO [11-28|17:10:22.367] HTTP server stopped                      endpoint=127.0.0.1:41571
TRACE[11-28|17:10:22.367] P2P networking is spinning down
    precompile_inclusion_test.go:94: goroutine 455538 [running]:
        runtime/debug.Stack()
        	/opt/hostedtoolcache/go/1.25.4/x64/src/runtime/debug/stack.go:26 +0x5e
        github.com/offchainlabs/nitro/util/testhelpers.RequireImpl({0x40e7a50, 0xc0b16cda40}, {0x40a52e0, 0xc139590660}, {0x0, 0x0, 0x0})
        	/home/runner/work/nitro/nitro/util/testhelpers/testhelpers.go:29 +0x55
        github.com/offchainlabs/nitro/system_tests.Require(0xc0b16cda40, {0x40a52e0, 0xc139590660}, {0x0, 0x0, 0x0})
        	/home/runner/work/nitro/nitro/system_tests/common_test.go:1790 +0x5d
        github.com/offchainlabs/nitro/system_tests.testPrecompiles(0xc0b16cda40, 0x1e, {0xc0765f7db0, 0x6, 0x0?})
        	/home/runner/work/nitro/nitro/system_tests/precompile_inclusion_test.go:94 +0x371
        github.com/offchainlabs/nitro/system_tests.TestVersion30(0xc0b16cda40?)
        	/home/runner/work/nitro/nitro/system_tests/precompile_inclusion_test.go:67 +0x798
        testing.tRunner(0xc0b16cda40, 0x3d2a6b8)
        	/opt/hostedtoolcache/go/1.25.4/x64/src/testing/testing.go:1934 +0xea
        created by testing.(*T).Run in goroutine 1
        	/opt/hostedtoolcache/go/1.25.4/x64/src/testing/testing.go:1997 +0x465
        
    precompile_inclusion_test.go:94: �[31;1m [] execution aborted (timeout = 5s) �[0;0m
--- FAIL: TestVersion30 (6.09s)

TestVersion40

Stack Traces | 6.560s run time

... [CONTENT TRUNCATED: Keeping last 20 lines]
INFO [11-28|17:10:21.905] HTTP server stopped                      endpoint=127.0.0.1:35639
TRACE[11-28|17:10:21.905] P2P networking is spinning down
    precompile_inclusion_test.go:94: goroutine 455539 [running]:
        runtime/debug.Stack()
        	/opt/hostedtoolcache/go/1.25.4/x64/src/runtime/debug/stack.go:26 +0x5e
        github.com/offchainlabs/nitro/util/testhelpers.RequireImpl({0x40e7a50, 0xc0b16cdc00}, {0x40a52e0, 0xc08c44d200}, {0x0, 0x0, 0x0})
        	/home/runner/work/nitro/nitro/util/testhelpers/testhelpers.go:29 +0x55
        github.com/offchainlabs/nitro/system_tests.Require(0xc0b16cdc00, {0x40a52e0, 0xc08c44d200}, {0x0, 0x0, 0x0})
        	/home/runner/work/nitro/nitro/system_tests/common_test.go:1790 +0x5d
        github.com/offchainlabs/nitro/system_tests.testPrecompiles(0xc0b16cdc00, 0x28, {0xc050b43df8, 0x5, 0x39?})
        	/home/runner/work/nitro/nitro/system_tests/precompile_inclusion_test.go:94 +0x371
        github.com/offchainlabs/nitro/system_tests.TestVersion40(0xc0b16cdc00?)
        	/home/runner/work/nitro/nitro/system_tests/precompile_inclusion_test.go:71 +0x64b
        testing.tRunner(0xc0b16cdc00, 0x3d2a6c0)
        	/opt/hostedtoolcache/go/1.25.4/x64/src/testing/testing.go:1934 +0xea
        created by testing.(*T).Run in goroutine 1
        	/opt/hostedtoolcache/go/1.25.4/x64/src/testing/testing.go:1997 +0x465
        
    precompile_inclusion_test.go:94: �[31;1m [] execution aborted (timeout = 5s) �[0;0m
--- FAIL: TestVersion40 (6.56s)

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arbos/constraints/multi_dimensional.go

arbos/l2pricing/l2pricing.go

arbos/l2pricing/model.go

gligneul · 2025-11-28T11:06:01Z

arbos/l2pricing/l2pricing.go

 const GethBlockGasLimit = 1 << 50
 const gasConstraintsMaxNum = 20
-const MaxExponentBips = arbmath.Bips(85_000)
+const multiGasConstraintsMaxNum = 10


10 might not be enough.

There is a related issue with retryable redeem: if we have more than 17 multi-gas constraints, storage would charge extra 15000 gas units for chunking (assumption). My suggestion is to put 15 for now and after NIT-4152 remove this limit

gligneul · 2025-11-28T11:07:21Z

arbos/l2pricing/l2pricing.go

+func (ps *L2PricingState) MultiGasConstraintsMaxNum() int {
+	return multiGasConstraintsMaxNum
+}


You can make the constant public instead of having this method.

gligneul · 2025-11-28T11:26:42Z

arbos/l2pricing/model.go

+}
+
+// GrowBacklog increases the backlog for the active pricing model.
+func (ps *L2PricingState) GrowBacklog(usedGas uint64, usedMultiGas multigas.MultiGas) error {


You split some functions into separate grow/shrink, but others continue to use the boolean constant, making the code look strange. I have another suggestion:

Suggested change

func (ps *L2PricingState) GrowBacklog(usedGas uint64, usedMultiGas multigas.MultiGas) error {

enum BacklogOp int

const (

Shrink BacklopOp = iota

Grow

)

func (ps *L2PricingState) UpdateBacklog(op BacklogOp, usedGas uint64, usedMultiGas multigas.MultiGas) error {

We can probably even make this parameter generic, but I'm not sure if Go can handle this:

Suggested change

func (ps *L2PricingState) GrowBacklog(usedGas uint64, usedMultiGas multigas.MultiGas) error {

func (ps *L2PricingState) UpdateBacklog[op BacklogOp](usedGas uint64, usedMultiGas multigas.MultiGas) error { ```

gligneul · 2025-11-28T11:40:10Z

arbos/l2pricing/model.go

+	if usedMultiGas.SingleGas() != usedGas {
+		log.Warn("usedGas does not match sum of usedMultiGas", "usedGas", usedGas, "usedMultiGas", usedMultiGas.SingleGas())
+	}


It is so easy to just ignore this warning. I'd rather remove this and think of a better way of testing that these numbers won't diverge.

Also, by the time we see this warning in production, it will be too late to fix it because we will have to support this divergence forever.

Removed for now, probably there is way to have a debug-only assertion

gligneul · 2025-11-28T11:42:38Z

arbos/constraints/multi_dimensional.go

+// IncrementBacklog increments the constraint backlog based on multi-dimensional gas usage
+func (c *MultiGasConstraint) IncrementBacklog(multiGas multigas.MultiGas) error {
+	totalBacklog, err := c.backlog.Get()


To be consistent with the other models, it would be better to receive the BacklogOp and call applyGasDelta

MishkaRogachev force-pushed the add-multi-dimensional-multi-constraint-pricer-algorithm branch from a3cb346 to 5dc32f7 Compare November 17, 2025 10:00

MishkaRogachev mentioned this pull request Nov 17, 2025

core: Add multigas to EndTxHook and safeDecrement OffchainLabs/go-ethereum#579

Open

MishkaRogachev force-pushed the add-multi-dimensional-multi-constraint-pricer-algorithm branch from 5dc32f7 to a7acb86 Compare November 17, 2025 11:21

MishkaRogachev force-pushed the add-multi-dimensional-multi-constraint-pricer-algorithm branch 2 times, most recently from 454b599 to 28a7a5f Compare November 18, 2025 13:44

MishkaRogachev marked this pull request as ready for review November 19, 2025 15:04

MishkaRogachev requested review from eljobe and gligneul November 19, 2025 15:04

MishkaRogachev assigned gligneul Nov 19, 2025

MishkaRogachev force-pushed the add-multi-dimensional-multi-constraint-pricer-algorithm branch from fa8781a to 4f2c34e Compare November 21, 2025 12:04

MishkaRogachev assigned MishkaRogachev and unassigned gligneul Nov 21, 2025

MishkaRogachev force-pushed the add-multi-dimensional-multi-constraint-pricer-algorithm branch from 8ec77cd to 0611789 Compare November 21, 2025 14:03

MishkaRogachev assigned gligneul and unassigned gligneul Nov 21, 2025

MishkaRogachev force-pushed the add-multi-dimensional-multi-constraint-pricer-algorithm branch 2 times, most recently from b14c464 to 46e002a Compare November 24, 2025 10:55

MishkaRogachev assigned gligneul and unassigned MishkaRogachev Nov 24, 2025

gligneul requested changes Nov 24, 2025

View reviewed changes

gligneul assigned MishkaRogachev and unassigned gligneul Nov 24, 2025

MishkaRogachev force-pushed the add-multi-dimensional-multi-constraint-pricer-algorithm branch 3 times, most recently from 0953140 to a138b23 Compare November 25, 2025 17:51

MishkaRogachev added 4 commits November 26, 2025 11:46

Replace ShouldUseGasConstraints with GasModelToUse

7dd37c4

Correct AddToGasPool signature to support multi-gas

83ba000

Implement multi-gas multi-constraints pricing formula

31993c5

Minor pricer improvments

764631d

MishkaRogachev added 5 commits November 26, 2025 11:46

Refactor and improve multi-gas price calculations

18b7978

Add log to addToGasPoolWithMultiGasConstraints

b705a5e

Fix flaky TestSetAndGetMultiGasPricingConstraints

2c6cb85

Post-merge mixes for redeem

abf4241

Separate AddToGasPool/SubstractGasFromPool in l2 pricing

9392bb1

MishkaRogachev force-pushed the add-multi-dimensional-multi-constraint-pricer-algorithm branch from a138b23 to 9392bb1 Compare November 26, 2025 10:47

Adjust backlog update cost and better namings

752c710

MishkaRogachev force-pushed the add-multi-dimensional-multi-constraint-pricer-algorithm branch from fd0e681 to 752c710 Compare November 26, 2025 15:43

MishkaRogachev requested a review from gligneul November 26, 2025 15:58

MishkaRogachev assigned gligneul and unassigned MishkaRogachev Nov 26, 2025

MishkaRogachev mentioned this pull request Nov 27, 2025

Issue refunds based on multi-dimensinal base fee #4082

Draft

gligneul requested changes Nov 28, 2025

View reviewed changes

gligneul assigned MishkaRogachev and unassigned gligneul Nov 28, 2025

MishkaRogachev assigned gligneul and unassigned MishkaRogachev Nov 28, 2025

MishkaRogachev requested a review from gligneul November 28, 2025 15:34

Merge constrains package to l2pricing & review fixes

09d57c1

MishkaRogachev force-pushed the add-multi-dimensional-multi-constraint-pricer-algorithm branch from c8f6c5a to 09d57c1 Compare November 28, 2025 16:53

-func (ps *L2PricingState) GrowBacklog(usedGas uint64, usedMultiGas multigas.MultiGas) error {
+enum BacklogOp int
+const (
+    Shrink BacklopOp = iota
+    Grow
+)
+func (ps *L2PricingState) UpdateBacklog(op BacklogOp, usedGas uint64, usedMultiGas multigas.MultiGas) error {

	func (ps *L2PricingState) GrowBacklog(usedGas uint64, usedMultiGas multigas.MultiGas) error {
	func (ps *L2PricingState) UpdateBacklog[op BacklogOp](usedGas uint64, usedMultiGas multigas.MultiGas) error { ```

Add multi dimensional multi constraint pricer algorithm #4012

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MishkaRogachev commented Nov 14, 2025 •

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