Add feature flag to enable shuffled index cache (#3893)

* add feature flag to enable shuffled index cache

* gaz'

beacon-chain/cache/shuffled_indices.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
+	"github.com/prysmaticlabs/prysm/shared/featureconfig"
 	"k8s.io/client-go/tools/cache"
 )
 
@@ -62,6 +63,9 @@ func NewShuffledIndicesCache() *ShuffledIndicesCache {
 // IndicesByIndexSeed fetches IndicesByIndexSeed by epoch and seed. Returns true with a
 // reference to the ShuffledIndicesInEpoch info, if exists. Otherwise returns false, nil.
 func (c *ShuffledIndicesCache) IndicesByIndexSeed(index uint64, seed []byte) ([]uint64, error) {
+	if !featureconfig.Get().EnableShuffledIndexCache {
+		return nil, nil
+	}
 	c.lock.RLock()
 	defer c.lock.RUnlock()
 	key := string(seed) + strconv.Itoa(int(index))
@@ -88,6 +92,9 @@ func (c *ShuffledIndicesCache) IndicesByIndexSeed(index uint64, seed []byte) ([]
 // AddShuffledValidatorList adds IndicesByIndexSeed object to the cache. This method also trims the least
 // recently added IndicesByIndexSeed object if the cache size has ready the max cache size limit.
 func (c *ShuffledIndicesCache) AddShuffledValidatorList(shuffledIndices *IndicesByIndexSeed) error {
+	if !featureconfig.Get().EnableShuffledIndexCache {
+		return nil
+	}
 	c.lock.Lock()
 	defer c.lock.Unlock()
 	if err := c.shuffledIndicesCache.AddIfNotPresent(shuffledIndices); err != nil {

beacon-chain/cache/shuffled_indices_test.go

@@ -4,8 +4,16 @@ import (
 	"reflect"
 	"strconv"
 	"testing"
+
+	"github.com/prysmaticlabs/prysm/shared/featureconfig"
 )
 
+func init() {
+	fc := featureconfig.Get()
+	fc.EnableShuffledIndexCache = true
+	featureconfig.Init(fc)
+}
+
 func TestShuffleKeyFn_OK(t *testing.T) {
 	sInfo := &IndicesByIndexSeed{
 		Index:           999,

beacon-chain/core/helpers/BUILD.bazel

@@ -60,6 +60,7 @@ go_test(
         "//proto/eth/v1alpha1:go_default_library",
         "//shared/bls:go_default_library",
         "//shared/bytesutil:go_default_library",
+        "//shared/featureconfig:go_default_library",
         "//shared/params:go_default_library",
         "//shared/sliceutil:go_default_library",
         "//shared/testutil:go_default_library",

beacon-chain/core/helpers/committee_test.go

@@ -9,6 +9,7 @@ import (
 	"github.com/prysmaticlabs/go-bitfield"
 	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
 	ethpb "github.com/prysmaticlabs/prysm/proto/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/featureconfig"
 	"github.com/prysmaticlabs/prysm/shared/params"
 	"github.com/prysmaticlabs/prysm/shared/sliceutil"
 	"google.golang.org/grpc/codes"
@@ -176,6 +177,11 @@ func TestComputeCommittee_WithoutCache(t *testing.T) {
 }
 
 func TestComputeCommittee_WithCache(t *testing.T) {
+	fc := featureconfig.Get()
+	fc.EnableShuffledIndexCache = true
+	featureconfig.Init(fc)
+	defer featureconfig.Init(nil)
+
 	// Create 10 committees
 	committeeCount := uint64(10)
 	validatorCount := committeeCount * params.BeaconConfig().TargetCommitteeSize

shared/featureconfig/config.go

@@ -36,10 +36,11 @@ type Flag struct {
 	EnableFinalizedBlockRootIndex bool // EnableFinalizedBlockRootIndex in the database. This operation may be expensive at runtime.
 
 	// Cache toggles.
-	EnableAttestationCache  bool // EnableAttestationCache; see https://github.com/prysmaticlabs/prysm/issues/3106.
-	EnableEth1DataVoteCache bool // EnableEth1DataVoteCache; see https://github.com/prysmaticlabs/prysm/issues/3106.
-	EnableNewCache          bool // EnableNewCache enables the node to use the new caching scheme.
-	EnableBLSPubkeyCache    bool // EnableBLSPubkeyCache to improve wall time of PubkeyFromBytes.
+	EnableAttestationCache   bool // EnableAttestationCache; see https://github.com/prysmaticlabs/prysm/issues/3106.
+	EnableEth1DataVoteCache  bool // EnableEth1DataVoteCache; see https://github.com/prysmaticlabs/prysm/issues/3106.
+	EnableNewCache           bool // EnableNewCache enables the node to use the new caching scheme.
+	EnableBLSPubkeyCache     bool // EnableBLSPubkeyCache to improve wall time of PubkeyFromBytes.
+	EnableShuffledIndexCache bool // EnableShuffledIndexCache to cache expensive shuffled index computation.
 }
 
 var featureConfig *Flag
@@ -114,6 +115,10 @@ func ConfigureBeaconChain(ctx *cli.Context) {
 		log.Warn("Enabled finalized block root index")
 		cfg.EnableFinalizedBlockRootIndex = true
 	}
+	if ctx.GlobalBool(enableShuffledIndexCache.Name) {
+		log.Warn("Enabled shuffled index cache.")
+		cfg.EnableShuffledIndexCache = true
+	}
 	Init(cfg)
 }
 

shared/featureconfig/flags.go

@@ -29,6 +29,10 @@ var (
 		Name:  "enable-eth1-data-vote-cache",
 		Usage: "Enable unsafe cache mechanism. See https://github.com/prysmaticlabs/prysm/issues/3106",
 	}
+	enableShuffledIndexCache = cli.BoolFlag{
+		Name:  "enable-shuffled-index-cache",
+		Usage: "Enable unsafe cache mechanism. See https://github.com/prysmaticlabs/prysm/issues/3106",
+	}
 	// InitSyncNoVerifyFlag enables the initial sync no verify configuration.
 	InitSyncNoVerifyFlag = cli.BoolFlag{
 		Name:  "init-sync-no-verify",
@@ -99,6 +103,7 @@ var BeaconChainFlags = append(deprecatedFlags, []cli.Flag{
 	OptimizeProcessEpoch,
 	enableBackupWebhookFlag,
 	enableBLSPubkeyCacheFlag,
+	enableShuffledIndexCache,
 	pruneFinalizedStatesFlag,
 	enableFinalizedBlockRootIndexFlag,
 }...)