crypto/kzg4844: do lazy init in all ckzg funcs

[jtraglia]

• Add ckzgIniter.Do(ckzgInit) call to all c-kzg functions.
• Add b.ResetTimer() in benchmarks for accuracy.
• Delete some unnecessary blank lines for consistency.
• Fix a minor typo in a comment.

[holiman]

--- FAIL: TestCKZGWithPoint (0.01s)
panic: trusted setup isn't loaded [recovered]
	panic: trusted setup isn't loaded
goroutine 18 [running]:
testing.tRunner.func1.2({0x5f3d20, 0x764108})
	/home/appveyor/.cache/geth-go-1.20.3-linux-amd64/go/src/testing/testing.go:1526 +0x24e
testing.tRunner.func1()
	/home/appveyor/.cache/geth-go-1.20.3-linux-amd64/go/src/testing/testing.go:1529 +0x39f
panic({0x5f3d20, 0x764108})
	/home/appveyor/.cache/geth-go-1.20.3-linux-amd64/go/src/runtime/panic.go:884 +0x213
github.com/ethereum/c-kzg-4844/bindings/go.BlobToKZGCommitment({0x15, 0xbc, 0x4c, 0x98, 0x23, 0xa3, 0xc0, 0xcd, 0xf, 0xdc, ...})
	/home/appveyor/.gvm/pkgsets/go1.20.1/global/pkg/mod/github.com/ethereum/c-kzg-4844@v0.3.0/bindings/go/main.go:208 +0x145
github.com/ethereum/go-ethereum/crypto/kzg4844.ckzgBlobToCommitment(...)
	/home/appveyor/projects/go-ethereum/crypto/kzg4844/kzg4844_ckzg_cgo.go:65
github.com/ethereum/go-ethereum/crypto/kzg4844.BlobToCommitment({0x15, 0xbc, 0x4c, 0x98, 0x23, 0xa3, 0xc0, 0xcd, 0xf, 0xdc, ...})
	/home/appveyor/projects/go-ethereum/crypto/kzg4844/kzg4844.go:70 +0xa5
github.com/ethereum/go-ethereum/crypto/kzg4844.testKZGWithPoint(0xc000085380, 0x1?)
	/home/appveyor/projects/go-ethereum/crypto/kzg4844/kzg4844_test.go:60 +0xe5
github.com/ethereum/go-ethereum/crypto/kzg4844.TestCKZGWithPoint(0x0?)
	/home/appveyor/projects/go-ethereum/crypto/kzg4844/kzg4844_test.go:48 +0x1e
testing.tRunner(0xc000085380, 0x72a6d8)
	/home/appveyor/.cache/geth-go-1.20.3-linux-amd64/go/src/testing/testing.go:1576 +0x10b
created by testing.(*T).Run
	/home/appveyor/.cache/geth-go-1.20.3-linux-amd64/go/src/testing/testing.go:1629 +0x3ea
FAIL	github.com/ethereum/go-ethereum/crypto/kzg4844	0.012s
ok  	github.com/ethereum/go-ethereum/crypto/secp256k1	2.402s

Tests call it directly, without doing the proper loading, so this PR breaks that

[jtraglia]

Ah sorry, I didn't notice that. I've made some changes to the test file that should fix this.

• Replace test setup with call to UseCKZG.
• Call b.ResetTimer() after setup, for accurate benchmarks.
• Remove a couple blank lines for consistency.

[jtraglia]

Also, from looking at the benchmarks I can tell that go-kzg is using concurrency. In Peter's comment about this a while back, it didn't seem like this was the desired behavior. Should I fix this in another PR?

• Some ops seem exceedingly slow on Apple M2 c-kzg-4844#290 (comment)

$ go test -tags=ckzg -bench=.                       
goos: darwin
goarch: arm64
pkg: github.com/ethereum/go-ethereum/crypto/kzg4844
BenchmarkCKZGBlobToCommitment-20              27          43707494 ns/op
BenchmarkGoKZGBlobToCommitment-20            288           4147987 ns/op
BenchmarkCKZGComputeProof-20                  26          44053894 ns/op
BenchmarkGoKZGComputeProof-20                240           5009865 ns/op
BenchmarkCKZGVerifyProof-20                 1144           1044147 ns/op
BenchmarkGoKZGVerifyProof-20                 794           1496341 ns/op
BenchmarkCKZGComputeBlobProof-20              26          43993462 ns/op
BenchmarkGoKZGComputeBlobProof-20            230           5166157 ns/op
BenchmarkCKZGVerifyBlobProof-20              697           1721706 ns/op
BenchmarkGoKZGVerifyBlobProof-20             534           2249320 ns/op

The last argument in go-kzg functions is numGoRoutines. Right now it's currently configured (with 0) to use all available CPU cores. If you want to disable this, change it to 1. For example, this function call:

go-ethereum/crypto/kzg4844/kzg4844_gokzg.go

Line 64 in aecf3f9

proof, claim, err := context.ComputeKZGProof((gokzg4844.Blob)(blob), (gokzg4844.Scalar)(point), 0)

[fjl]

We reviewed this in a team call, and it seems not great to call UseCKZG in every test. The original 'issue' this PR was supposed to fix is that there is a call like ckzgIniter.Do(ckzgInit) in the low level function. Thing is, that call is basically free, so I think we could just go ahead and leave the lazy initialization in.

[karalabe]

This seems a simpler fix that's also consistent with the go version

diff --git a/crypto/kzg4844/kzg4844_ckzg_cgo.go b/crypto/kzg4844/kzg4844_ckzg_cgo.go
index d62ca3fad..540028569 100644
--- a/crypto/kzg4844/kzg4844_ckzg_cgo.go
+++ b/crypto/kzg4844/kzg4844_ckzg_cgo.go
@@ -74,6 +74,8 @@ func ckzgBlobToCommitment(blob Blob) (Commitment, error) {
 // ckzgComputeProof computes the KZG proof at the given point for the polynomial
 // represented by the blob.
 func ckzgComputeProof(blob Blob, point Point) (Proof, Claim, error) {
+       ckzgIniter.Do(ckzgInit)
+
        proof, claim, err := ckzg4844.ComputeKZGProof((ckzg4844.Blob)(blob), (ckzg4844.Bytes32)(point))
        if err != nil {
                return Proof{}, Claim{}, err
@@ -84,6 +86,8 @@ func ckzgComputeProof(blob Blob, point Point) (Proof, Claim, error) {
 // ckzgVerifyProof verifies the KZG proof that the polynomial represented by the blob
 // evaluated at the given point is the claimed value.
 func ckzgVerifyProof(commitment Commitment, point Point, claim Claim, proof Proof) error {
+       ckzgIniter.Do(ckzgInit)
+
        valid, err := ckzg4844.VerifyKZGProof((ckzg4844.Bytes48)(commitment), (ckzg4844.Bytes32)(point), (ckzg4844.Bytes32)(claim), (ckzg4844.Bytes48)(proof))
        if err != nil {
                return err
@@ -99,6 +103,8 @@ func ckzgVerifyProof(commitment Commitment, point Point, claim Claim, proof Proo
 //
 // This method does not verify that the commitment is correct with respect to blob.
 func ckzgComputeBlobProof(blob Blob, commitment Commitment) (Proof, error) {
+       ckzgIniter.Do(ckzgInit)
+
        proof, err := ckzg4844.ComputeBlobKZGProof((ckzg4844.Blob)(blob), (ckzg4844.Bytes48)(commitment))
        if err != nil {
                return Proof{}, err
@@ -108,6 +114,8 @@ func ckzgComputeBlobProof(blob Blob, commitment Commitment) (Proof, error) {
 
 // ckzgVerifyBlobProof verifies that the blob data corresponds to the provided commitment.
 func ckzgVerifyBlobProof(blob Blob, commitment Commitment, proof Proof) error {
+       ckzgIniter.Do(ckzgInit)
+
        valid, err := ckzg4844.VerifyBlobKZGProof((ckzg4844.Blob)(blob), (ckzg4844.Bytes48)(commitment), (ckzg4844.Bytes48)(proof))
        if err != nil {
                return err

[jtraglia]

@fjl Okay, no worries. I understand. I've made a new commit that should resolve this.

[karalabe]

LGTM thanks!