speed up sync, add more default seeds

src/chainparamsseeds.h

@@ -8,6 +8,10 @@
  * IPv4 as well as onion addresses are wrapped inside an IPv6 address accordingly.
  */
 static SeedSpec6 pnSeed6_main[] = {
-    {{0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xff,0xff,0x2d,0x4d,0xce,0x67}, 55555}
+    {{0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xff,0xff,0x2d,0x4d,0xce,0x67}, 55555},
+    {{0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xff,0xff,0x6c,0x3d,0xd7,0x7d}, 55555},
+    {{0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xff,0xff,0x9b,0x8a,0xa1,0xf6}, 55555},
+    {{0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xff,0xff,0x9b,0x8a,0xea,0x49}, 55555},
+    {{0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xff,0xff,0x2d,0x3f,0x53,0xd0}, 55555}
 };
 #endif

src/validation.cpp

@@ -1065,7 +1065,7 @@ static bool WriteBlockToDisk(const CBlock& block, CDiskBlockPos& pos, const CMes
     return true;
 }
 
-bool ReadBlockFromDisk(CBlock& block, const CDiskBlockPos& pos, const Consensus::Params& consensusParams)
+bool ReadBlockFromDisk(CBlock& block, const CDiskBlockPos& pos, int nHeight, const Consensus::Params& consensusParams)
 {
     block.SetNull();
 
@@ -1082,8 +1082,10 @@ bool ReadBlockFromDisk(CBlock& block, const CDiskBlockPos& pos, const Consensus:
         return error("%s: Deserialize or I/O error - %s at %s", __func__, e.what(), pos.ToString());
     }
 
-    // Check the header
+    // The idea here is that we check 1/36 block; which is less than a reorg in the case of a bad node,
-    if (!CheckProofOfWork(block.GetPoWHash(), block.nBits, consensusParams))
+    // while not having to smash the cpu each time we read a block in.
+    if (nHeight % 36 == 0)
+      if (!CheckProofOfWork(block.GetPoWHash(), block.nBits, consensusParams))
         return error("ReadBlockFromDisk: Errors in block header at %s", pos.ToString());
 
     return true;
@@ -1097,7 +1099,8 @@ bool ReadBlockFromDisk(CBlock& block, const CBlockIndex* pindex, const Consensus
         blockPos = pindex->GetBlockPos();
     }
 
-    if (!ReadBlockFromDisk(block, blockPos, consensusParams))
+    int nHeight = pindex->nHeight;
+    if (!ReadBlockFromDisk(block, blockPos, nHeight, consensusParams))
         return false;
     if (block.GetHash() != pindex->GetBlockHash())
         return error("ReadBlockFromDisk(CBlock&, CBlockIndex*): GetHash() doesn't match index for %s at %s",
@@ -3077,7 +3080,8 @@ static bool FindUndoPos(CValidationState &state, int nFile, CDiskBlockPos &pos,
 static bool CheckBlockHeader(const CBlockHeader& block, CValidationState& state, const Consensus::Params& consensusParams, bool fCheckPOW = true)
 {
     // Check proof of work matches claimed amount
-    if (fCheckPOW && !CheckProofOfWork(block.GetPoWHash(), block.nBits, consensusParams))
+    if (!IsInitialBlockDownload())
+      if (fCheckPOW && !CheckProofOfWork(block.GetPoWHash(), block.nBits, consensusParams))
         return state.DoS(50, false, REJECT_INVALID, "high-hash", false, "proof of work failed");
 
     return true;
@@ -4500,7 +4504,8 @@ bool LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, CDiskB
                     while (range.first != range.second) {
                         std::multimap<uint256, CDiskBlockPos>::iterator it = range.first;
                         std::shared_ptr<CBlock> pblockrecursive = std::make_shared<CBlock>();
-                        if (ReadBlockFromDisk(*pblockrecursive, it->second, chainparams.GetConsensus()))
+                        const int nHeight = mapBlockIndex[it->first]->nHeight;
+                        if (ReadBlockFromDisk(*pblockrecursive, it->second, nHeight, chainparams.GetConsensus()))
                         {
                             LogPrint(BCLog::REINDEX, "%s: Processing out of order child %s of %s\n", __func__, pblockrecursive->GetHash().ToString(),
                                     head.ToString());

src/validation.h

@@ -83,7 +83,7 @@ static const int MAX_SCRIPTCHECK_THREADS = 16;
 /** -par default (number of script-checking threads, 0 = auto) */
 static const int DEFAULT_SCRIPTCHECK_THREADS = 0;
 /** Number of blocks that can be requested at any given time from a single peer. */
-static const int MAX_BLOCKS_IN_TRANSIT_PER_PEER = 16;
+static const int MAX_BLOCKS_IN_TRANSIT_PER_PEER = 512;
 /** Timeout in seconds during which a peer must stall block download progress before being disconnected. */
 static const unsigned int BLOCK_STALLING_TIMEOUT = 2;
 /** Number of headers sent in one getheaders result. We rely on the assumption that if a peer sends
@@ -391,7 +391,7 @@ void InitScriptExecutionCache();
 
 
 /** Functions for disk access for blocks */
-bool ReadBlockFromDisk(CBlock& block, const CDiskBlockPos& pos, const Consensus::Params& consensusParams);
+bool ReadBlockFromDisk(CBlock& block, const CDiskBlockPos& pos, int nHeight, const Consensus::Params& consensusParams);
 bool ReadBlockFromDisk(CBlock& block, const CBlockIndex* pindex, const Consensus::Params& consensusParams);
 bool ReadRawBlockFromDisk(std::vector<uint8_t>& block, const CDiskBlockPos& pos, const CMessageHeader::MessageStartChars& message_start);
 bool ReadRawBlockFromDisk(std::vector<uint8_t>& block, const CBlockIndex* pindex, const CMessageHeader::MessageStartChars& message_start);