src/miner.cpp

   1 // Copyright (c) 2009-2010 Satoshi Nakamoto
   2 // Copyright (c) 2009-2012 The Bitcoin developers
   3 // Distributed under the MIT/X11 software license, see the accompanying
   4 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
   5
   6 #include "core.h"
   7 #include "wallet.h"
   8 #include "miner.h"
   9 #include "main.h"
  10
  11
  12
  13
  14
  15
  16 //////////////////////////////////////////////////////////////////////////////
  17 //
  18 // BitcoinMiner
  19 //
  20
  21 int static FormatHashBlocks(void* pbuffer, unsigned int len)
  22 {
  23     unsigned char* pdata = (unsigned char*)pbuffer;
  24     unsigned int blocks = 1 + ((len + 8) / 64);
  25     unsigned char* pend = pdata + 64 * blocks;
  26     memset(pdata + len, 0, 64 * blocks - len);
  27     pdata[len] = 0x80;
  28     unsigned int bits = len * 8;
  29     pend[-1] = (bits >> 0) & 0xff;
  30     pend[-2] = (bits >> 8) & 0xff;
  31     pend[-3] = (bits >> 16) & 0xff;
  32     pend[-4] = (bits >> 24) & 0xff;
  33     return blocks;
  34 }
  35
  36 static const unsigned int pSHA256InitState[8] =
  37 {0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19};
  38
  39 void SHA256Transform(void* pstate, void* pinput, const void* pinit)
  40 {
  41     SHA256_CTX ctx;
  42     unsigned char data[64];
  43
  44     SHA256_Init(&ctx);
  45
  46     for (int i = 0; i < 16; i++)
  47         ((uint32_t*)data)[i] = ByteReverse(((uint32_t*)pinput)[i]);
  48
  49     for (int i = 0; i < 8; i++)
  50         ctx.h[i] = ((uint32_t*)pinit)[i];
  51
  52     SHA256_Update(&ctx, data, sizeof(data));
  53     for (int i = 0; i < 8; i++)
  54         ((uint32_t*)pstate)[i] = ctx.h[i];
  55 }
  56
  57 //
  58 // ScanHash scans nonces looking for a hash with at least some zero bits.
  59 // It operates on big endian data.  Caller does the byte reversing.
  60 // All input buffers are 16-byte aligned.  nNonce is usually preserved
  61 // between calls, but periodically or if nNonce is 0xffff0000 or above,
  62 // the block is rebuilt and nNonce starts over at zero.
  63 //
  64 unsigned int static ScanHash_CryptoPP(char* pmidstate, char* pdata, char* phash1, char* phash, unsigned int& nHashesDone)
  65 {
  66     unsigned int& nNonce = *(unsigned int*)(pdata + 12);
  67     for (;;)
  68     {
  69         // Crypto++ SHA256
  70         // Hash pdata using pmidstate as the starting state into
  71         // pre-formatted buffer phash1, then hash phash1 into phash
  72         nNonce++;
  73         SHA256Transform(phash1, pdata, pmidstate);
  74         SHA256Transform(phash, phash1, pSHA256InitState);
  75
  76         // Return the nonce if the hash has at least some zero bits,
  77         // caller will check if it has enough to reach the target
  78         if (((unsigned short*)phash)[14] == 0)
  79             return nNonce;
  80
  81         // If nothing found after trying for a while, return -1
  82         if ((nNonce & 0xffff) == 0)
  83         {
  84             nHashesDone = 0xffff+1;
  85             return (unsigned int) -1;
  86         }
  87         if ((nNonce & 0xfff) == 0)
  88             boost::this_thread::interruption_point();
  89     }
  90 }
  91
  92 // Some explaining would be appreciated
  93 class COrphan
  94 {
  95 public:
  96     CTransaction* ptx;
  97     set<uint256> setDependsOn;
  98     double dPriority;
  99     double dFeePerKb;
 100
 101     COrphan(CTransaction* ptxIn)
 102     {
 103         ptx = ptxIn;
 104         dPriority = dFeePerKb = 0;
 105     }
 106
 107     void print() const
 108     {
 109         printf("COrphan(hash=%s, dPriority=%.1f, dFeePerKb=%.1f)\n",
 110                ptx->GetHash().ToString().c_str(), dPriority, dFeePerKb);
 111         BOOST_FOREACH(uint256 hash, setDependsOn)
 112             printf("   setDependsOn %s\n", hash.ToString().c_str());
 113     }
 114 };
 115
 116
 117 uint64 nLastBlockTx = 0;
 118 uint64 nLastBlockSize = 0;
 119
 120 // We want to sort transactions by priority and fee, so:
 121 typedef boost::tuple<double, double, CTransaction*> TxPriority;
 122 class TxPriorityCompare
 123 {
 124     bool byFee;
 125 public:
 126     TxPriorityCompare(bool _byFee) : byFee(_byFee) { }
 127     bool operator()(const TxPriority& a, const TxPriority& b)
 128     {
 129         if (byFee)
 130         {
 131             if (a.get<1>() == b.get<1>())
 132                 return a.get<0>() < b.get<0>();
 133             return a.get<1>() < b.get<1>();
 134         }
 135         else
 136         {
 137             if (a.get<0>() == b.get<0>())
 138                 return a.get<1>() < b.get<1>();
 139             return a.get<0>() < b.get<0>();
 140         }
 141     }
 142 };
 143
 144 CBlockTemplate* CreateNewBlock(CReserveKey& reservekey)
 145 {
 146     // Create new block
 147     auto_ptr<CBlockTemplate> pblocktemplate(new CBlockTemplate());
 148     if(!pblocktemplate.get())
 149         return NULL;
 150     CBlock *pblock = &pblocktemplate->block; // pointer for convenience
 151
 152     // Create coinbase tx
 153     CTransaction txNew;
 154     txNew.vin.resize(1);
 155     txNew.vin[0].prevout.SetNull();
 156     txNew.vout.resize(1);
 157     CPubKey pubkey;
 158     if (!reservekey.GetReservedKey(pubkey))
 159         return NULL;
 160     txNew.vout[0].scriptPubKey << pubkey << OP_CHECKSIG;
 161
 162     // Add our coinbase tx as first transaction
 163     pblock->vtx.push_back(txNew);
 164     pblocktemplate->vTxFees.push_back(-1); // updated at end
 165     pblocktemplate->vTxSigOps.push_back(-1); // updated at end
 166
 167     // Largest block you're willing to create:
 168     unsigned int nBlockMaxSize = GetArg("-blockmaxsize", MAX_BLOCK_SIZE_GEN/2);
 169     // Limit to betweeen 1K and MAX_BLOCK_SIZE-1K for sanity:
 170     nBlockMaxSize = std::max((unsigned int)1000, std::min((unsigned int)(MAX_BLOCK_SIZE-1000), nBlockMaxSize));
 171
 172     // How much of the block should be dedicated to high-priority transactions,
 173     // included regardless of the fees they pay
 174     unsigned int nBlockPrioritySize = GetArg("-blockprioritysize", DEFAULT_BLOCK_PRIORITY_SIZE);
 175     nBlockPrioritySize = std::min(nBlockMaxSize, nBlockPrioritySize);
 176
 177     // Minimum block size you want to create; block will be filled with free transactions
 178     // until there are no more or the block reaches this size:
 179     unsigned int nBlockMinSize = GetArg("-blockminsize", 0);
 180     nBlockMinSize = std::min(nBlockMaxSize, nBlockMinSize);
 181
 182     // Collect memory pool transactions into the block
 183     int64 nFees = 0;
 184     {
 185         LOCK2(cs_main, mempool.cs);
 186         CBlockIndex* pindexPrev = pindexBest;
 187         CCoinsViewCache view(*pcoinsTip, true);
 188
 189         // Priority order to process transactions
 190         list<COrphan> vOrphan; // list memory doesn't move
 191         map<uint256, vector<COrphan*> > mapDependers;
 192         bool fPrintPriority = GetBoolArg("-printpriority", false);
 193
 194         // This vector will be sorted into a priority queue:
 195         vector<TxPriority> vecPriority;
 196         vecPriority.reserve(mempool.mapTx.size());
 197         for (map<uint256, CTransaction>::iterator mi = mempool.mapTx.begin(); mi != mempool.mapTx.end(); ++mi)
 198         {
 199             CTransaction& tx = (*mi).second;
 200             if (tx.IsCoinBase() || !IsFinalTx(tx))
 201                 continue;
 202
 203             COrphan* porphan = NULL;
 204             double dPriority = 0;
 205             int64 nTotalIn = 0;
 206             bool fMissingInputs = false;
 207             BOOST_FOREACH(const CTxIn& txin, tx.vin)
 208             {
 209                 // Read prev transaction
 210                 if (!view.HaveCoins(txin.prevout.hash))
 211                 {
 212                     // This should never happen; all transactions in the memory
 213                     // pool should connect to either transactions in the chain
 214                     // or other transactions in the memory pool.
 215                     if (!mempool.mapTx.count(txin.prevout.hash))
 216                     {
 217                         printf("ERROR: mempool transaction missing input\n");
 218                         if (fDebug) assert("mempool transaction missing input" == 0);
 219                         fMissingInputs = true;
 220                         if (porphan)
 221                             vOrphan.pop_back();
 222                         break;
 223                     }
 224
 225                     // Has to wait for dependencies
 226                     if (!porphan)
 227                     {
 228                         // Use list for automatic deletion
 229                         vOrphan.push_back(COrphan(&tx));
 230                         porphan = &vOrphan.back();
 231                     }
 232                     mapDependers[txin.prevout.hash].push_back(porphan);
 233                     porphan->setDependsOn.insert(txin.prevout.hash);
 234                     nTotalIn += mempool.mapTx[txin.prevout.hash].vout[txin.prevout.n].nValue;
 235                     continue;
 236                 }
 237                 const CCoins &coins = view.GetCoins(txin.prevout.hash);
 238
 239                 int64 nValueIn = coins.vout[txin.prevout.n].nValue;
 240                 nTotalIn += nValueIn;
 241
 242                 int nConf = pindexPrev->nHeight - coins.nHeight + 1;
 243
 244                 dPriority += (double)nValueIn * nConf;
 245             }
 246             if (fMissingInputs) continue;
 247
 248             // Priority is sum(valuein * age) / txsize
 249             unsigned int nTxSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
 250             dPriority /= nTxSize;
 251
 252             // This is a more accurate fee-per-kilobyte than is used by the client code, because the
 253             // client code rounds up the size to the nearest 1K. That's good, because it gives an
 254             // incentive to create smaller transactions.
 255             double dFeePerKb =  double(nTotalIn-GetValueOut(tx)) / (double(nTxSize)/1000.0);
 256
 257             if (porphan)
 258             {
 259                 porphan->dPriority = dPriority;
 260                 porphan->dFeePerKb = dFeePerKb;
 261             }
 262             else
 263                 vecPriority.push_back(TxPriority(dPriority, dFeePerKb, &(*mi).second));
 264         }
 265
 266         // Collect transactions into block
 267         uint64 nBlockSize = 1000;
 268         uint64 nBlockTx = 0;
 269         int nBlockSigOps = 100;
 270         bool fSortedByFee = (nBlockPrioritySize <= 0);
 271
 272         TxPriorityCompare comparer(fSortedByFee);
 273         std::make_heap(vecPriority.begin(), vecPriority.end(), comparer);
 274
 275         while (!vecPriority.empty())
 276         {
 277             // Take highest priority transaction off the priority queue:
 278             double dPriority = vecPriority.front().get<0>();
 279             double dFeePerKb = vecPriority.front().get<1>();
 280             CTransaction& tx = *(vecPriority.front().get<2>());
 281
 282             std::pop_heap(vecPriority.begin(), vecPriority.end(), comparer);
 283             vecPriority.pop_back();
 284
 285             // Size limits
 286             unsigned int nTxSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
 287             if (nBlockSize + nTxSize >= nBlockMaxSize)
 288                 continue;
 289
 290             // Legacy limits on sigOps:
 291             unsigned int nTxSigOps = GetLegacySigOpCount(tx);
 292             if (nBlockSigOps + nTxSigOps >= MAX_BLOCK_SIGOPS)
 293                 continue;
 294
 295             // Skip free transactions if we're past the minimum block size:
 296             if (fSortedByFee && (dFeePerKb < CTransaction::nMinTxFee) && (nBlockSize + nTxSize >= nBlockMinSize))
 297                 continue;
 298
 299             // Prioritize by fee once past the priority size or we run out of high-priority
 300             // transactions:
 301             if (!fSortedByFee &&
 302                 ((nBlockSize + nTxSize >= nBlockPrioritySize) || !AllowFree(dPriority)))
 303             {
 304                 fSortedByFee = true;
 305                 comparer = TxPriorityCompare(fSortedByFee);
 306                 std::make_heap(vecPriority.begin(), vecPriority.end(), comparer);
 307             }
 308
 309             if (!view.HaveInputs(tx))
 310                 continue;
 311
 312             int64 nTxFees = view.GetValueIn(tx)-GetValueOut(tx);
 313
 314             nTxSigOps += GetP2SHSigOpCount(tx, view);
 315             if (nBlockSigOps + nTxSigOps >= MAX_BLOCK_SIGOPS)
 316                 continue;
 317
 318             CValidationState state;
 319             if (!CheckInputs(tx, state, view, true, SCRIPT_VERIFY_P2SH))
 320                 continue;
 321
 322             CTxUndo txundo;
 323             uint256 hash = tx.GetHash();
 324             UpdateCoins(tx, state, view, txundo, pindexPrev->nHeight+1, hash);
 325
 326             // Added
 327             pblock->vtx.push_back(tx);
 328             pblocktemplate->vTxFees.push_back(nTxFees);
 329             pblocktemplate->vTxSigOps.push_back(nTxSigOps);
 330             nBlockSize += nTxSize;
 331             ++nBlockTx;
 332             nBlockSigOps += nTxSigOps;
 333             nFees += nTxFees;
 334
 335             if (fPrintPriority)
 336             {
 337                 printf("priority %.1f feeperkb %.1f txid %s\n",
 338                        dPriority, dFeePerKb, tx.GetHash().ToString().c_str());
 339             }
 340
 341             // Add transactions that depend on this one to the priority queue
 342             if (mapDependers.count(hash))
 343             {
 344                 BOOST_FOREACH(COrphan* porphan, mapDependers[hash])
 345                 {
 346                     if (!porphan->setDependsOn.empty())
 347                     {
 348                         porphan->setDependsOn.erase(hash);
 349                         if (porphan->setDependsOn.empty())
 350                         {
 351                             vecPriority.push_back(TxPriority(porphan->dPriority, porphan->dFeePerKb, porphan->ptx));
 352                             std::push_heap(vecPriority.begin(), vecPriority.end(), comparer);
 353                         }
 354                     }
 355                 }
 356             }
 357         }
 358
 359         nLastBlockTx = nBlockTx;
 360         nLastBlockSize = nBlockSize;
 361         printf("CreateNewBlock(): total size %"PRI64u"\n", nBlockSize);
 362
 363         pblock->vtx[0].vout[0].nValue = GetBlockValue(pindexPrev->nHeight+1, nFees);
 364         pblocktemplate->vTxFees[0] = -nFees;
 365
 366         // Fill in header
 367         pblock->hashPrevBlock  = pindexPrev->GetBlockHash();
 368         UpdateTime(*pblock, pindexPrev);
 369         pblock->nBits          = GetNextWorkRequired(pindexPrev, pblock);
 370         pblock->nNonce         = 0;
 371         pblock->vtx[0].vin[0].scriptSig = CScript() << OP_0 << OP_0;
 372         pblocktemplate->vTxSigOps[0] = GetLegacySigOpCount(pblock->vtx[0]);
 373
 374         CBlockIndex indexDummy(*pblock);
 375         indexDummy.pprev = pindexPrev;
 376         indexDummy.nHeight = pindexPrev->nHeight + 1;
 377         CCoinsViewCache viewNew(*pcoinsTip, true);
 378         CValidationState state;
 379         if (!ConnectBlock(*pblock, state, &indexDummy, viewNew, true))
 380             throw std::runtime_error("CreateNewBlock() : ConnectBlock failed");
 381     }
 382
 383     return pblocktemplate.release();
 384 }
 385
 386
 387 void IncrementExtraNonce(CBlock* pblock, CBlockIndex* pindexPrev, unsigned int& nExtraNonce)
 388 {
 389     // Update nExtraNonce
 390     static uint256 hashPrevBlock;
 391     if (hashPrevBlock != pblock->hashPrevBlock)
 392     {
 393         nExtraNonce = 0;
 394         hashPrevBlock = pblock->hashPrevBlock;
 395     }
 396     ++nExtraNonce;
 397     unsigned int nHeight = pindexPrev->nHeight+1; // Height first in coinbase required for block.version=2
 398     pblock->vtx[0].vin[0].scriptSig = (CScript() << nHeight << CBigNum(nExtraNonce)) + COINBASE_FLAGS;
 399     assert(pblock->vtx[0].vin[0].scriptSig.size() <= 100);
 400
 401     pblock->hashMerkleRoot = pblock->BuildMerkleTree();
 402 }
 403
 404
 405 void FormatHashBuffers(CBlock* pblock, char* pmidstate, char* pdata, char* phash1)
 406 {
 407     //
 408     // Pre-build hash buffers
 409     //
 410     struct
 411     {
 412         struct unnamed2
 413         {
 414             int nVersion;
 415             uint256 hashPrevBlock;
 416             uint256 hashMerkleRoot;
 417             unsigned int nTime;
 418             unsigned int nBits;
 419             unsigned int nNonce;
 420         }
 421         block;
 422         unsigned char pchPadding0[64];
 423         uint256 hash1;
 424         unsigned char pchPadding1[64];
 425     }
 426     tmp;
 427     memset(&tmp, 0, sizeof(tmp));
 428
 429     tmp.block.nVersion       = pblock->nVersion;
 430     tmp.block.hashPrevBlock  = pblock->hashPrevBlock;
 431     tmp.block.hashMerkleRoot = pblock->hashMerkleRoot;
 432     tmp.block.nTime          = pblock->nTime;
 433     tmp.block.nBits          = pblock->nBits;
 434     tmp.block.nNonce         = pblock->nNonce;
 435
 436     FormatHashBlocks(&tmp.block, sizeof(tmp.block));
 437     FormatHashBlocks(&tmp.hash1, sizeof(tmp.hash1));
 438
 439     // Byte swap all the input buffer
 440     for (unsigned int i = 0; i < sizeof(tmp)/4; i++)
 441         ((unsigned int*)&tmp)[i] = ByteReverse(((unsigned int*)&tmp)[i]);
 442
 443     // Precalc the first half of the first hash, which stays constant
 444     SHA256Transform(pmidstate, &tmp.block, pSHA256InitState);
 445
 446     memcpy(pdata, &tmp.block, 128);
 447     memcpy(phash1, &tmp.hash1, 64);
 448 }
 449
 450
 451 bool CheckWork(CBlock* pblock, CWallet& wallet, CReserveKey& reservekey)
 452 {
 453     uint256 hash = pblock->GetHash();
 454     uint256 hashTarget = CBigNum().SetCompact(pblock->nBits).getuint256();
 455
 456     if (hash > hashTarget)
 457         return false;
 458
 459     //// debug print
 460     printf("BitcoinMiner:\n");
 461     printf("proof-of-work found  \n  hash: %s  \ntarget: %s\n", hash.GetHex().c_str(), hashTarget.GetHex().c_str());
 462     pblock->print();
 463     printf("generated %s\n", FormatMoney(pblock->vtx[0].vout[0].nValue).c_str());
 464
 465     // Found a solution
 466     {
 467         LOCK(cs_main);
 468         if (pblock->hashPrevBlock != hashBestChain)
 469             return error("BitcoinMiner : generated block is stale");
 470
 471         // Remove key from key pool
 472         reservekey.KeepKey();
 473
 474         // Track how many getdata requests this block gets
 475         {
 476             LOCK(wallet.cs_wallet);
 477             wallet.mapRequestCount[pblock->GetHash()] = 0;
 478         }
 479
 480         // Process this block the same as if we had received it from another node
 481         CValidationState state;
 482         if (!ProcessBlock(state, NULL, pblock))
 483             return error("BitcoinMiner : ProcessBlock, block not accepted");
 484     }
 485
 486     return true;
 487 }
 488
 489 void static BitcoinMiner(CWallet *pwallet)
 490 {
 491     printf("BitcoinMiner started\n");
 492     SetThreadPriority(THREAD_PRIORITY_LOWEST);
 493     RenameThread("bitcoin-miner");
 494
 495     // Each thread has its own key and counter
 496     CReserveKey reservekey(pwallet);
 497     unsigned int nExtraNonce = 0;
 498
 499     try { while (true) {
 500         if (Params().NetworkID() != CChainParams::REGTEST) {
 501             // Busy-wait for the network to come online so we don't waste time mining
 502             // on an obsolete chain. In regtest mode we expect to fly solo.
 503             while (vNodes.empty())
 504                 MilliSleep(1000);
 505         }
 506
 507         //
 508         // Create new block
 509         //
 510         unsigned int nTransactionsUpdatedLast = nTransactionsUpdated;
 511         CBlockIndex* pindexPrev = pindexBest;
 512
 513         auto_ptr<CBlockTemplate> pblocktemplate(CreateNewBlock(reservekey));
 514         if (!pblocktemplate.get())
 515             return;
 516         CBlock *pblock = &pblocktemplate->block;
 517         IncrementExtraNonce(pblock, pindexPrev, nExtraNonce);
 518
 519         printf("Running BitcoinMiner with %"PRIszu" transactions in block (%u bytes)\n", pblock->vtx.size(),
 520                ::GetSerializeSize(*pblock, SER_NETWORK, PROTOCOL_VERSION));
 521
 522         //
 523         // Pre-build hash buffers
 524         //
 525         char pmidstatebuf[32+16]; char* pmidstate = alignup<16>(pmidstatebuf);
 526         char pdatabuf[128+16];    char* pdata     = alignup<16>(pdatabuf);
 527         char phash1buf[64+16];    char* phash1    = alignup<16>(phash1buf);
 528
 529         FormatHashBuffers(pblock, pmidstate, pdata, phash1);
 530
 531         unsigned int& nBlockTime = *(unsigned int*)(pdata + 64 + 4);
 532         unsigned int& nBlockBits = *(unsigned int*)(pdata + 64 + 8);
 533         unsigned int& nBlockNonce = *(unsigned int*)(pdata + 64 + 12);
 534
 535
 536         //
 537         // Search
 538         //
 539         int64 nStart = GetTime();
 540         uint256 hashTarget = CBigNum().SetCompact(pblock->nBits).getuint256();
 541         uint256 hashbuf[2];
 542         uint256& hash = *alignup<16>(hashbuf);
 543         while (true)
 544         {
 545             unsigned int nHashesDone = 0;
 546             unsigned int nNonceFound;
 547
 548             // Crypto++ SHA256
 549             nNonceFound = ScanHash_CryptoPP(pmidstate, pdata + 64, phash1,
 550                                             (char*)&hash, nHashesDone);
 551
 552             // Check if something found
 553             if (nNonceFound != (unsigned int) -1)
 554             {
 555                 for (unsigned int i = 0; i < sizeof(hash)/4; i++)
 556                     ((unsigned int*)&hash)[i] = ByteReverse(((unsigned int*)&hash)[i]);
 557
 558                 if (hash <= hashTarget)
 559                 {
 560                     // Found a solution
 561                     pblock->nNonce = ByteReverse(nNonceFound);
 562                     assert(hash == pblock->GetHash());
 563
 564                     SetThreadPriority(THREAD_PRIORITY_NORMAL);
 565                     CheckWork(pblock, *pwallet, reservekey);
 566                     SetThreadPriority(THREAD_PRIORITY_LOWEST);
 567
 568                     // In regression test mode, stop mining after a block is found. This
 569                     // allows developers to controllably generate a block on demand.
 570                     if (Params().NetworkID() == CChainParams::REGTEST)
 571                         throw boost::thread_interrupted();
 572
 573                     break;
 574                 }
 575             }
 576
 577             // Meter hashes/sec
 578             static int64 nHashCounter;
 579             if (nHPSTimerStart == 0)
 580             {
 581                 nHPSTimerStart = GetTimeMillis();
 582                 nHashCounter = 0;
 583             }
 584             else
 585                 nHashCounter += nHashesDone;
 586             if (GetTimeMillis() - nHPSTimerStart > 4000)
 587             {
 588                 static CCriticalSection cs;
 589                 {
 590                     LOCK(cs);
 591                     if (GetTimeMillis() - nHPSTimerStart > 4000)
 592                     {
 593                         dHashesPerSec = 1000.0 * nHashCounter / (GetTimeMillis() - nHPSTimerStart);
 594                         nHPSTimerStart = GetTimeMillis();
 595                         nHashCounter = 0;
 596                         static int64 nLogTime;
 597                         if (GetTime() - nLogTime > 30 * 60)
 598                         {
 599                             nLogTime = GetTime();
 600                             printf("hashmeter %6.0f khash/s\n", dHashesPerSec/1000.0);
 601                         }
 602                     }
 603                 }
 604             }
 605
 606             // Check for stop or if block needs to be rebuilt
 607             boost::this_thread::interruption_point();
 608             if (vNodes.empty() && Params().NetworkID() != CChainParams::REGTEST)
 609                 break;
 610             if (nBlockNonce >= 0xffff0000)
 611                 break;
 612             if (nTransactionsUpdated != nTransactionsUpdatedLast && GetTime() - nStart > 60)
 613                 break;
 614             if (pindexPrev != pindexBest)
 615                 break;
 616
 617             // Update nTime every few seconds
 618             UpdateTime(*pblock, pindexPrev);
 619             nBlockTime = ByteReverse(pblock->nTime);
 620             if (TestNet())
 621             {
 622                 // Changing pblock->nTime can change work required on testnet:
 623                 nBlockBits = ByteReverse(pblock->nBits);
 624                 hashTarget = CBigNum().SetCompact(pblock->nBits).getuint256();
 625             }
 626         }
 627     } }
 628     catch (boost::thread_interrupted)
 629     {
 630         printf("BitcoinMiner terminated\n");
 631         throw;
 632     }
 633 }
 634
 635 void GenerateBitcoins(bool fGenerate, CWallet* pwallet)
 636 {
 637     static boost::thread_group* minerThreads = NULL;
 638
 639     int nThreads = GetArg("-genproclimit", -1);
 640     if (nThreads < 0) {
 641         if (Params().NetworkID() == CChainParams::REGTEST)
 642             nThreads = 1;
 643         else
 644             nThreads = boost::thread::hardware_concurrency();
 645     }
 646
 647     if (minerThreads != NULL)
 648     {
 649         minerThreads->interrupt_all();
 650         delete minerThreads;
 651         minerThreads = NULL;
 652     }
 653
 654     if (nThreads == 0 || !fGenerate)
 655         return;
 656
 657     minerThreads = new boost::thread_group();
 658     for (int i = 0; i < nThreads; i++)
 659         minerThreads->create_thread(boost::bind(&BitcoinMiner, pwallet));
 660 }
 661
 662
 663