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When creating new blocks, sort 'paid' area by fee-per-kb

Modify CreateNewBlock so that instead of processing all transactions
in priority order, process the first 27K of transactions in
priority order and then process the rest in fee-per-kilobyte
order.

This is the first, minimal step towards better a better fee-handling
system for both miners and end-users; this patch should be easy
to backport to the old versions of Bitcoin, and accomplishes the
most important goal-- allow users to "buy their way in" to blocks
using transaction fees.
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1 parent 29c8fb0 commit c555400ca134991e39d5e3a565fcd2215abe56f6 @gavinandresen gavinandresen committed Jul 12, 2012
Showing with 114 additions and 31 deletions.
  1. +5 −0 src/init.cpp
  2. +109 −31 src/main.cpp
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@@ -279,6 +279,11 @@ std::string HelpMessage()
" -checkblocks=<n> " + _("How many blocks to check at startup (default: 2500, 0 = all)") + "\n" +
" -checklevel=<n> " + _("How thorough the block verification is (0-6, default: 1)") + "\n" +
" -loadblock=<file> " + _("Imports blocks from external blk000?.dat file") + "\n" +
+ _("\nBlock creation options:\n") +
+ " -blockminsize=<n> " + _("Minimum size, in bytes (default: 0)\n") +
+ " -blockmaxsize=<n> " + _("Maximum size, in bytes (default: 250000)\n") +
+ " -blockprioritysize=<n> " + _("Maximum bytes of high-priority/low-fee transactions (default: 27000)\n") +
+
" -? " + _("This help message") + "\n";
strUsage += string() +
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@@ -3312,16 +3312,18 @@ class COrphan
CTransaction* ptx;
set<uint256> setDependsOn;
double dPriority;
+ double dFeePerKb;
COrphan(CTransaction* ptxIn)
{
ptx = ptxIn;
- dPriority = 0;
+ dPriority = dFeePerKb = 0;
}
void print() const
{
- printf("COrphan(hash=%s, dPriority=%.1f)\n", ptx->GetHash().ToString().substr(0,10).c_str(), dPriority);
+ printf("COrphan(hash=%s, dPriority=%.1f, dFeePerKb=%.1f)\n",
+ ptx->GetHash().ToString().substr(0,10).c_str(), dPriority, dFeePerKb);
BOOST_FOREACH(uint256 hash, setDependsOn)
printf(" setDependsOn %s\n", hash.ToString().substr(0,10).c_str());
}
@@ -3331,6 +3333,30 @@ class COrphan
uint64 nLastBlockTx = 0;
uint64 nLastBlockSize = 0;
+// We want to sort transactions by priority and fee, so:
+typedef boost::tuple<double, double, CTransaction*> TxPriority;
+class TxPriorityCompare
+{
+ bool byFee;
+public:
+ TxPriorityCompare(bool _byFee) : byFee(_byFee) { }
+ bool operator()(const TxPriority& a, const TxPriority& b)
+ {
+ if (byFee)
+ {
+ if (a.get<1>() == b.get<1>())
+ return a.get<0>() < b.get<0>();
+ return a.get<1>() < b.get<1>();
+ }
+ else
+ {
+ if (a.get<0>() == b.get<0>())
+ return a.get<1>() < b.get<1>();
+ return a.get<0>() < b.get<0>();
+ }
+ }
+};
+
const char* pszDummy = "\0\0";
CScript scriptDummy(std::vector<unsigned char>(pszDummy, pszDummy + sizeof(pszDummy)));
@@ -3353,6 +3379,30 @@ CBlock* CreateNewBlock(CReserveKey& reservekey)
// Add our coinbase tx as first transaction
pblock->vtx.push_back(txNew);
+ // Largest block you're willing to create:
+ unsigned int nBlockMaxSize = GetArg("-blockmaxsize", MAX_BLOCK_SIZE_GEN/2);
+ // Limit to betweeen 1K and MAX_BLOCK_SIZE-1K for sanity:
+ nBlockMaxSize = std::max((unsigned int)1000, std::min((unsigned int)(MAX_BLOCK_SIZE-1000), nBlockMaxSize));
+
+ // How much of the block should be dedicated to high-priority transactions,
+ // included regardless of the fees they pay
+ unsigned int nBlockPrioritySize = GetArg("-blockprioritysize", 27000);
+ nBlockPrioritySize = std::min(nBlockMaxSize, nBlockPrioritySize);
+
+ // Minimum block size you want to create; block will be filled with free transactions
+ // until there are no more or the block reaches this size:
+ unsigned int nBlockMinSize = GetArg("-blockminsize", 0);
+ nBlockMinSize = std::min(nBlockMaxSize, nBlockMinSize);
+
+ // Fee-per-kilobyte amount considered the same as "free"
+ // Be careful setting this: if you set it to zero then
+ // a transaction spammer can cheaply fill blocks using
+ // 1-satoshi-fee transactions. It should be set above the real
+ // cost to you of processing a transaction.
+ int64 nMinTxFee = MIN_TX_FEE;
+ if (mapArgs.count("-mintxfee"))
+ ParseMoney(mapArgs["-mintxfee"], nMinTxFee);
+
// Collect memory pool transactions into the block
int64 nFees = 0;
{
@@ -3362,7 +3412,10 @@ CBlock* CreateNewBlock(CReserveKey& reservekey)
// Priority order to process transactions
list<COrphan> vOrphan; // list memory doesn't move
map<uint256, vector<COrphan*> > mapDependers;
- multimap<double, CTransaction*> mapPriority;
+
+ // This vector will be sorted into a priority queue:
+ vector<TxPriority> vecPriority;
+ vecPriority.reserve(mempool.mapTx.size());
for (map<uint256, CTransaction>::iterator mi = mempool.mapTx.begin(); mi != mempool.mapTx.end(); ++mi)
{
CTransaction& tx = (*mi).second;
@@ -3371,6 +3424,7 @@ CBlock* CreateNewBlock(CReserveKey& reservekey)
COrphan* porphan = NULL;
double dPriority = 0;
+ int64 nTotalIn = 0;
BOOST_FOREACH(const CTxIn& txin, tx.vin)
{
// Read prev transaction
@@ -3387,61 +3441,77 @@ CBlock* CreateNewBlock(CReserveKey& reservekey)
}
mapDependers[txin.prevout.hash].push_back(porphan);
porphan->setDependsOn.insert(txin.prevout.hash);
+ nTotalIn += mempool.mapTx[txin.prevout.hash].vout[txin.prevout.n].nValue;
continue;
}
int64 nValueIn = txPrev.vout[txin.prevout.n].nValue;
+ nTotalIn += nValueIn;
- // Read block header
int nConf = txindex.GetDepthInMainChain();
-
dPriority += (double)nValueIn * nConf;
-
- if (fDebug && GetBoolArg("-printpriority"))
- printf("priority nValueIn=%-12"PRI64d" nConf=%-5d dPriority=%-20.1f\n", nValueIn, nConf, dPriority);
}
// Priority is sum(valuein * age) / txsize
- dPriority /= ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
+ unsigned int nTxSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
+ dPriority /= nTxSize;
- if (porphan)
- porphan->dPriority = dPriority;
- else
- mapPriority.insert(make_pair(-dPriority, &(*mi).second));
+ // This is a more accurate fee-per-kilobyte than is used by the client code, because the
+ // client code rounds up the size to the nearest 1K. That's good, because it gives an
+ // incentive to create smaller transactions.
+ double dFeePerKb = double(nTotalIn-tx.GetValueOut()) / (double(nTxSize)/1000.0);
- if (fDebug && GetBoolArg("-printpriority"))
+ if (porphan)
{
- printf("priority %-20.1f %s\n%s", dPriority, tx.GetHash().ToString().substr(0,10).c_str(), tx.ToString().c_str());
- if (porphan)
- porphan->print();
- printf("\n");
+ porphan->dPriority = dPriority;
+ porphan->dFeePerKb = dFeePerKb;
}
+ else
+ vecPriority.push_back(TxPriority(dPriority, dFeePerKb, &(*mi).second));
}
// Collect transactions into block
map<uint256, CTxIndex> mapTestPool;
uint64 nBlockSize = 1000;
uint64 nBlockTx = 0;
int nBlockSigOps = 100;
- while (!mapPriority.empty())
+ bool fSortedByFee = (nBlockPrioritySize <= 0);
+
+ TxPriorityCompare comparer(fSortedByFee);
+ std::make_heap(vecPriority.begin(), vecPriority.end(), comparer);
+
+ while (!vecPriority.empty())
{
- // Take highest priority transaction off priority queue
- double dPriority = -(*mapPriority.begin()).first;
- CTransaction& tx = *(*mapPriority.begin()).second;
- mapPriority.erase(mapPriority.begin());
+ // Take highest priority transaction off the priority queue:
+ double dPriority = vecPriority.front().get<0>();
+ double dFeePerKb = vecPriority.front().get<1>();
+ CTransaction& tx = *(vecPriority.front().get<2>());
+
+ std::pop_heap(vecPriority.begin(), vecPriority.end(), comparer);
+ vecPriority.pop_back();
// Size limits
unsigned int nTxSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
- if (nBlockSize + nTxSize >= MAX_BLOCK_SIZE_GEN)
+ if (nBlockSize + nTxSize >= nBlockMaxSize)
continue;
// Legacy limits on sigOps:
unsigned int nTxSigOps = tx.GetLegacySigOpCount();
if (nBlockSigOps + nTxSigOps >= MAX_BLOCK_SIGOPS)
continue;
- // Transaction fee required depends on block size
- bool fAllowFree = (nBlockSize + nTxSize < 4000 || CTransaction::AllowFree(dPriority));
- int64 nMinFee = tx.GetMinFee(nBlockSize, fAllowFree, GMF_BLOCK);
+ // Skip free transactions if we're past the minimum block size:
+ if (fSortedByFee && (dFeePerKb < nMinTxFee) && (nBlockSize + nTxSize >= nBlockMinSize))
+ continue;
+
+ // Prioritize by fee once past the priority size or we run out of high-priority
+ // transactions:
+ if (!fSortedByFee &&
+ ((nBlockSize + nTxSize >= nBlockPrioritySize) || (dPriority < COIN * 144 / 250)))
+ {
+ fSortedByFee = true;
+ comparer = TxPriorityCompare(fSortedByFee);
+ std::make_heap(vecPriority.begin(), vecPriority.end(), comparer);
+ }
// Connecting shouldn't fail due to dependency on other memory pool transactions
// because we're already processing them in order of dependency
@@ -3452,8 +3522,6 @@ CBlock* CreateNewBlock(CReserveKey& reservekey)
continue;
int64 nTxFees = tx.GetValueIn(mapInputs)-tx.GetValueOut();
- if (nTxFees < nMinFee)
- continue;
nTxSigOps += tx.GetP2SHSigOpCount(mapInputs);
if (nBlockSigOps + nTxSigOps >= MAX_BLOCK_SIGOPS)
@@ -3471,6 +3539,12 @@ CBlock* CreateNewBlock(CReserveKey& reservekey)
nBlockSigOps += nTxSigOps;
nFees += nTxFees;
+ if (fDebug && GetBoolArg("-printpriority"))
+ {
+ printf("priority %.1f feeperkb %.1f txid %s\n",
+ dPriority, dFeePerKb, tx.GetHash().ToString().c_str());
+ }
+
// Add transactions that depend on this one to the priority queue
uint256 hash = tx.GetHash();
if (mapDependers.count(hash))
@@ -3481,7 +3555,10 @@ CBlock* CreateNewBlock(CReserveKey& reservekey)
{
porphan->setDependsOn.erase(hash);
if (porphan->setDependsOn.empty())
- mapPriority.insert(make_pair(-porphan->dPriority, porphan->ptx));
+ {
+ vecPriority.push_back(TxPriority(porphan->dPriority, porphan->dFeePerKb, porphan->ptx));
+ std::push_heap(vecPriority.begin(), vecPriority.end(), comparer);
+ }
}
}
}
@@ -3654,7 +3731,8 @@ void static BitcoinMiner(CWallet *pwallet)
return;
IncrementExtraNonce(pblock.get(), pindexPrev, nExtraNonce);
- printf("Running BitcoinMiner with %d transactions in block\n", pblock->vtx.size());
+ printf("Running BitcoinMiner with %d transactions in block (%u bytes)\n", pblock->vtx.size(),
+ ::GetSerializeSize(*pblock, SER_NETWORK, PROTOCOL_VERSION));
//

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