Gnosis. Only one Block Processor thread running, slow syncing.

[terrancewong]

Description

There's only one block processor thread running, slow syncing.

Steps to Reproduce

gnosis.cfg

{
  "Init": {
    "ChainSpecPath": "chainspec/gnosis.json",
    "GenesisHash": "0x4f1dd23188aab3a76b463e4af801b52b1248ef073c648cbdc4c9333d3da79756",
    "BaseDbPath": "nethermind_db/gnosis",
    "LogFileName": "gnosis.logs.txt",
    "LogRules": "logs:INFO",
    "MemoryHint": 8589934592
  },
  "JsonRpc": {
    "Enabled": true,
    "EnginePort": 8551,
    "EnabledModules": ["admin", "eth", "net", "txpool", "web3"],
    "JwtSecretFile": "../jwt.hex"
  },
  "Sync": {
    "MaxProcessingThreads": 16,
    "FastSync": false,
    "FastBlocks": false,
    "TuneDbMode": "DisableCompaction"
  },
  "Pruning": {
    "Mode": "None"
  },
  "Blocks": {
    "SecondsPerSlot": 5,
    "TargetBlockGasLimit": 17000000
  },
  "Mining": {
    "MinGasPrice": "1000000000"
  },
  "EthStats": {
    "Name": "Nethermind Gnosis"
  },
  "Receipt": {
    "TxLookupLimit": 0
  },
  "Metrics": {
    "NodeName": "Gnosis"
  },
  "Bloom": {
    "IndexLevelBucketSizes": [
      16,
      16,
      16
    ]
  },
  "Network": {
    "MaxActivePeers": 64,
    "ProcessingThreadCount": 8,
    "P2PPort": 30303,
    "DiscoveryPort": 30303,
    "EnableUPnP": false,
    "MaxOutgoingConnectsPerSec": 32
  },
  "Db" :{
    "StateDbBlockSize": 16384,
    "CompactionReadAhead": 262144
  }
}

Block downloaded more than 26M, and processing blocks at ~14M

Actual behavior

in atop, press 'y' to show all threads, there is only one Block Processor. only ~100% CPU used by nethermind

Expected behavior

Using more threads to speed up block processing.