[Performance] AutocombineDust is called less often

Autocombine to the threshold and not above
Autocombine now start later
->wait for 5mn old block or younger

Author: Warrows

src/wallet.cpp

@@ -3991,11 +3991,11 @@ void CWallet::AutoZeromint()
 
 void CWallet::AutoCombineDust()
 {
-    if (IsInitialBlockDownload() || IsLocked()) {
+    if (chainActive.Tip()->nTime < (GetAdjustedTime() - 300) || IsLocked()) {
         return;
     }
 
-    map<CBitcoinAddress, vector<COutput> > mapCoinsByAddress = AvailableCoinsByAddress(true, 0);
+    map<CBitcoinAddress, vector<COutput> > mapCoinsByAddress = AvailableCoinsByAddress(true, nAutoCombineThreshold * COIN);
 
     //coins are sectioned by address. This combination code only wants to combine inputs that belong to the same address
     for (map<CBitcoinAddress, vector<COutput> >::iterator it = mapCoinsByAddress.begin(); it != mapCoinsByAddress.end(); it++) {
@@ -4014,13 +4014,15 @@ void CWallet::AutoCombineDust()
             if (out.tx->IsCoinStake() && out.tx->GetDepthInMainChain() < COINBASE_MATURITY + 1)
                 continue;
 
-            if (out.Value() > nAutoCombineThreshold * COIN)
-                continue;
-
             COutPoint outpt(out.tx->GetHash(), out.i);
             coinControl->Select(outpt);
             vRewardCoins.push_back(out);
             nTotalRewardsValue += out.Value();
+
+            // Combine to the threshold and not way above
+            if (nTotalRewardsValue > nAutoCombineThreshold * COIN)
+                break;
+
             // Around 180 bytes per input. We use 190 to be certain
             txSizeEstimate += 190;
             if (txSizeEstimate >= MAX_STANDARD_TX_SIZE - 200)
@@ -4055,6 +4057,10 @@ void CWallet::AutoCombineDust()
             continue;
         }
 
+        //we don't combine below the threshold unless the fees are 0 to avoid paying fees over fees over fees
+        if (vecSend[0].second < nAutoCombineThreshold * COIN && nFeeRet > 0)
+            continue;
+
         if (!CommitTransaction(wtx, keyChange)) {
             LogPrintf("AutoCombineDust transaction commit failed\n");
             continue;