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authorKaz Wesley <keziahw@gmail.com>2016-04-30 21:45:26 -0700
committerKaz Wesley <keziahw@gmail.com>2016-06-02 12:31:51 -0700
commit9805f4af7ecb6becf8a146bd845fb131ffa625c9 (patch)
tree4be823065e49b4bd5bbe50e19b7c1d7a1b4bf929 /src
parent03cf6e86750218f633498210923544f4a6c3c020 (diff)
mapNextTx: use pointer as key, simplify value
Saves about 10% of application memory usage once the mempool warms up. Since the mempool is DynamicUsage-regulated, this will translate to a larger mempool in the same amount of space. Map value type: eliminate the vin index; no users of the map need to know which input of the transaction is spending the prevout. Map key type: replace the COutPoint with a pointer to a COutPoint. A COutPoint is 36 bytes, but each COutPoint is accessible from the same map entry's value. A trivial DereferencingComparator functor allows indirect map keys, but the resulting syntax is misleading: `map.find(&outpoint)`. Implement an indirectmap that acts as a wrapper to a map that uses a DereferencingComparator, supporting a syntax that accurately reflect the container's semantics: inserts and iterators use pointers since they store pointers and need them to remain constant and dereferenceable, but lookup functions take const references.
Diffstat (limited to 'src')
-rw-r--r--src/Makefile.am1
-rw-r--r--src/indirectmap.h52
-rw-r--r--src/main.cpp5
-rw-r--r--src/memusage.h16
-rw-r--r--src/txmempool.cpp46
-rw-r--r--src/txmempool.h17
6 files changed, 96 insertions, 41 deletions
diff --git a/src/Makefile.am b/src/Makefile.am
index 3c056386fa..ad61e4f108 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -94,6 +94,7 @@ BITCOIN_CORE_H = \
core_memusage.h \
httprpc.h \
httpserver.h \
+ indirectmap.h \
init.h \
key.h \
keystore.h \
diff --git a/src/indirectmap.h b/src/indirectmap.h
new file mode 100644
index 0000000000..28e1e8dedd
--- /dev/null
+++ b/src/indirectmap.h
@@ -0,0 +1,52 @@
+#ifndef BITCOIN_INDIRECTMAP_H
+#define BITCOIN_INDIRECTMAP_H
+
+template <class T>
+struct DereferencingComparator { bool operator()(const T a, const T b) const { return *a < *b; } };
+
+/* Map whose keys are pointers, but are compared by their dereferenced values.
+ *
+ * Differs from a plain std::map<const K*, T, DereferencingComparator<K*> > in
+ * that methods that take a key for comparison take a K rather than taking a K*
+ * (taking a K* would be confusing, since it's the value rather than the address
+ * of the object for comparison that matters due to the dereferencing comparator).
+ *
+ * Objects pointed to by keys must not be modified in any way that changes the
+ * result of DereferencingComparator.
+ */
+template <class K, class T>
+class indirectmap {
+private:
+ typedef std::map<const K*, T, DereferencingComparator<const K*> > base;
+ base m;
+public:
+ typedef typename base::iterator iterator;
+ typedef typename base::const_iterator const_iterator;
+ typedef typename base::size_type size_type;
+ typedef typename base::value_type value_type;
+
+ // passthrough (pointer interface)
+ std::pair<iterator, bool> insert(const value_type& value) { return m.insert(value); }
+
+ // pass address (value interface)
+ iterator find(const K& key) { return m.find(&key); }
+ const_iterator find(const K& key) const { return m.find(&key); }
+ iterator lower_bound(const K& key) { return m.lower_bound(&key); }
+ const_iterator lower_bound(const K& key) const { return m.lower_bound(&key); }
+ size_type erase(const K& key) { return m.erase(&key); }
+ size_type count(const K& key) const { return m.count(&key); }
+
+ // passthrough
+ bool empty() const { return m.empty(); }
+ size_type size() const { return m.size(); }
+ size_type max_size() const { return m.max_size(); }
+ void clear() { m.clear(); }
+ iterator begin() { return m.begin(); }
+ iterator end() { return m.end(); }
+ const_iterator begin() const { return m.begin(); }
+ const_iterator end() const { return m.end(); }
+ const_iterator cbegin() const { return m.cbegin(); }
+ const_iterator cend() const { return m.cend(); }
+};
+
+#endif // BITCOIN_INDIRECTMAP_H
diff --git a/src/main.cpp b/src/main.cpp
index 11ccab253e..13da2137e5 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1049,9 +1049,10 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const C
LOCK(pool.cs); // protect pool.mapNextTx
BOOST_FOREACH(const CTxIn &txin, tx.vin)
{
- if (pool.mapNextTx.count(txin.prevout))
+ auto itConflicting = pool.mapNextTx.find(txin.prevout);
+ if (itConflicting != pool.mapNextTx.end())
{
- const CTransaction *ptxConflicting = pool.mapNextTx[txin.prevout].ptx;
+ const CTransaction *ptxConflicting = itConflicting->second;
if (!setConflicts.count(ptxConflicting->GetHash()))
{
// Allow opt-out of transaction replacement by setting
diff --git a/src/memusage.h b/src/memusage.h
index 49760e64c7..9c98e5c2cf 100644
--- a/src/memusage.h
+++ b/src/memusage.h
@@ -5,6 +5,8 @@
#ifndef BITCOIN_MEMUSAGE_H
#define BITCOIN_MEMUSAGE_H
+#include "indirectmap.h"
+
#include <stdlib.h>
#include <map>
@@ -106,6 +108,20 @@ static inline size_t IncrementalDynamicUsage(const std::map<X, Y, Z>& m)
return MallocUsage(sizeof(stl_tree_node<std::pair<const X, Y> >));
}
+// indirectmap has underlying map with pointer as key
+
+template<typename X, typename Y>
+static inline size_t DynamicUsage(const indirectmap<X, Y>& m)
+{
+ return MallocUsage(sizeof(stl_tree_node<std::pair<const X*, Y> >)) * m.size();
+}
+
+template<typename X, typename Y>
+static inline size_t IncrementalDynamicUsage(const indirectmap<X, Y>& m)
+{
+ return MallocUsage(sizeof(stl_tree_node<std::pair<const X*, Y> >));
+}
+
// Boost data structures
template<typename X>
diff --git a/src/txmempool.cpp b/src/txmempool.cpp
index 52c7793118..d7fb77661b 100644
--- a/src/txmempool.cpp
+++ b/src/txmempool.cpp
@@ -147,11 +147,11 @@ void CTxMemPool::UpdateTransactionsFromBlock(const std::vector<uint256> &vHashes
if (it == mapTx.end()) {
continue;
}
- std::map<COutPoint, CInPoint>::iterator iter = mapNextTx.lower_bound(COutPoint(hash, 0));
+ auto iter = mapNextTx.lower_bound(COutPoint(hash, 0));
// First calculate the children, and update setMemPoolChildren to
// include them, and update their setMemPoolParents to include this tx.
- for (; iter != mapNextTx.end() && iter->first.hash == hash; ++iter) {
- const uint256 &childHash = iter->second.ptx->GetHash();
+ for (; iter != mapNextTx.end() && iter->first->hash == hash; ++iter) {
+ const uint256 &childHash = iter->second->GetHash();
txiter childIter = mapTx.find(childHash);
assert(childIter != mapTx.end());
// We can skip updating entries we've encountered before or that
@@ -365,11 +365,11 @@ void CTxMemPool::pruneSpent(const uint256 &hashTx, CCoins &coins)
{
LOCK(cs);
- std::map<COutPoint, CInPoint>::iterator it = mapNextTx.lower_bound(COutPoint(hashTx, 0));
+ auto it = mapNextTx.lower_bound(COutPoint(hashTx, 0));
// iterate over all COutPoints in mapNextTx whose hash equals the provided hashTx
- while (it != mapNextTx.end() && it->first.hash == hashTx) {
- coins.Spend(it->first.n); // and remove those outputs from coins
+ while (it != mapNextTx.end() && it->first->hash == hashTx) {
+ coins.Spend(it->first->n); // and remove those outputs from coins
it++;
}
}
@@ -414,7 +414,7 @@ bool CTxMemPool::addUnchecked(const uint256& hash, const CTxMemPoolEntry &entry,
const CTransaction& tx = newit->GetTx();
std::set<uint256> setParentTransactions;
for (unsigned int i = 0; i < tx.vin.size(); i++) {
- mapNextTx[tx.vin[i].prevout] = CInPoint(&tx, i);
+ mapNextTx.insert(std::make_pair(&tx.vin[i].prevout, &tx));
setParentTransactions.insert(tx.vin[i].prevout.hash);
}
// Don't bother worrying about child transactions of this one.
@@ -500,10 +500,10 @@ void CTxMemPool::removeRecursive(const CTransaction &origTx, std::list<CTransact
// happen during chain re-orgs if origTx isn't re-accepted into
// the mempool for any reason.
for (unsigned int i = 0; i < origTx.vout.size(); i++) {
- std::map<COutPoint, CInPoint>::iterator it = mapNextTx.find(COutPoint(origTx.GetHash(), i));
+ auto it = mapNextTx.find(COutPoint(origTx.GetHash(), i));
if (it == mapNextTx.end())
continue;
- txiter nextit = mapTx.find(it->second.ptx->GetHash());
+ txiter nextit = mapTx.find(it->second->GetHash());
assert(nextit != mapTx.end());
txToRemove.insert(nextit);
}
@@ -561,9 +561,9 @@ void CTxMemPool::removeConflicts(const CTransaction &tx, std::list<CTransaction>
list<CTransaction> result;
LOCK(cs);
BOOST_FOREACH(const CTxIn &txin, tx.vin) {
- std::map<COutPoint, CInPoint>::iterator it = mapNextTx.find(txin.prevout);
+ auto it = mapNextTx.find(txin.prevout);
if (it != mapNextTx.end()) {
- const CTransaction &txConflict = *it->second.ptx;
+ const CTransaction &txConflict = *it->second;
if (txConflict != tx)
{
removeRecursive(txConflict, removed);
@@ -671,10 +671,10 @@ void CTxMemPool::check(const CCoinsViewCache *pcoins) const
assert(coins && coins->IsAvailable(txin.prevout.n));
}
// Check whether its inputs are marked in mapNextTx.
- std::map<COutPoint, CInPoint>::const_iterator it3 = mapNextTx.find(txin.prevout);
+ auto it3 = mapNextTx.find(txin.prevout);
assert(it3 != mapNextTx.end());
- assert(it3->second.ptx == &tx);
- assert(it3->second.n == i);
+ assert(it3->first == &txin.prevout);
+ assert(it3->second == &tx);
i++;
}
assert(setParentCheck == GetMemPoolParents(it));
@@ -701,10 +701,10 @@ void CTxMemPool::check(const CCoinsViewCache *pcoins) const
// Check children against mapNextTx
CTxMemPool::setEntries setChildrenCheck;
- std::map<COutPoint, CInPoint>::const_iterator iter = mapNextTx.lower_bound(COutPoint(it->GetTx().GetHash(), 0));
+ auto iter = mapNextTx.lower_bound(COutPoint(it->GetTx().GetHash(), 0));
int64_t childSizes = 0;
- for (; iter != mapNextTx.end() && iter->first.hash == it->GetTx().GetHash(); ++iter) {
- txiter childit = mapTx.find(iter->second.ptx->GetHash());
+ for (; iter != mapNextTx.end() && iter->first->hash == it->GetTx().GetHash(); ++iter) {
+ txiter childit = mapTx.find(iter->second->GetHash());
assert(childit != mapTx.end()); // mapNextTx points to in-mempool transactions
if (setChildrenCheck.insert(childit).second) {
childSizes += childit->GetTxSize();
@@ -738,14 +738,12 @@ void CTxMemPool::check(const CCoinsViewCache *pcoins) const
stepsSinceLastRemove = 0;
}
}
- for (std::map<COutPoint, CInPoint>::const_iterator it = mapNextTx.begin(); it != mapNextTx.end(); it++) {
- uint256 hash = it->second.ptx->GetHash();
+ for (auto it = mapNextTx.cbegin(); it != mapNextTx.cend(); it++) {
+ uint256 hash = it->second->GetHash();
indexed_transaction_set::const_iterator it2 = mapTx.find(hash);
const CTransaction& tx = it2->GetTx();
assert(it2 != mapTx.end());
- assert(&tx == it->second.ptx);
- assert(tx.vin.size() > it->second.n);
- assert(it->first == it->second.ptx->vin[it->second.n].prevout);
+ assert(&tx == it->second);
}
assert(totalTxSize == checkTotal);
@@ -1044,8 +1042,8 @@ void CTxMemPool::TrimToSize(size_t sizelimit, std::vector<uint256>* pvNoSpendsRe
BOOST_FOREACH(const CTxIn& txin, tx.vin) {
if (exists(txin.prevout.hash))
continue;
- std::map<COutPoint, CInPoint>::iterator it = mapNextTx.lower_bound(COutPoint(txin.prevout.hash, 0));
- if (it == mapNextTx.end() || it->first.hash != txin.prevout.hash)
+ auto it = mapNextTx.lower_bound(COutPoint(txin.prevout.hash, 0));
+ if (it == mapNextTx.end() || it->first->hash != txin.prevout.hash)
pvNoSpendsRemaining->push_back(txin.prevout.hash);
}
}
diff --git a/src/txmempool.h b/src/txmempool.h
index de4ba0b371..7ad5579a06 100644
--- a/src/txmempool.h
+++ b/src/txmempool.h
@@ -11,6 +11,7 @@
#include "amount.h"
#include "coins.h"
+#include "indirectmap.h"
#include "primitives/transaction.h"
#include "sync.h"
@@ -305,20 +306,6 @@ struct ancestor_score {};
class CBlockPolicyEstimator;
-/** An inpoint - a combination of a transaction and an index n into its vin */
-class CInPoint
-{
-public:
- const CTransaction* ptx;
- uint32_t n;
-
- CInPoint() { SetNull(); }
- CInPoint(const CTransaction* ptxIn, uint32_t nIn) { ptx = ptxIn; n = nIn; }
- void SetNull() { ptx = NULL; n = (uint32_t) -1; }
- bool IsNull() const { return (ptx == NULL && n == (uint32_t) -1); }
- size_t DynamicMemoryUsage() const { return 0; }
-};
-
/**
* CTxMemPool stores valid-according-to-the-current-best-chain
* transactions that may be included in the next block.
@@ -477,7 +464,7 @@ private:
void UpdateChild(txiter entry, txiter child, bool add);
public:
- std::map<COutPoint, CInPoint> mapNextTx;
+ indirectmap<COutPoint, const CTransaction*> mapNextTx;
std::map<uint256, std::pair<double, CAmount> > mapDeltas;
/** Create a new CTxMemPool.