Merge pull request #2527 from LefterisJP/respect_no_precompute

ensurePrecomputed should respect no_precompute argument V2

eth/main.cpp

@@ -1700,6 +1700,7 @@ int main(int argc, char** argv)
 		c->setGasPricer(gasPricer);
 		c->setForceMining(forceMining);
 		// TODO: expose sealant interface.
+		c->setShouldPrecomputeDAG(m.shouldPrecompute());
 		c->setTurboMining(m.minerType() == MinerCLI::MinerType::GPU);
 		c->setAddress(beneficiary);
 		c->setNetworkId(networkId);

ethminer/MinerAux.h

@@ -380,6 +380,7 @@ public:
 	};
 
 	MinerType minerType() const { return m_minerType; }
+	bool shouldPrecompute() const { return m_precompute; }
 
 private:
 	void doInitDAG(unsigned _n)

libethcore/EthashSealEngine.cpp

@@ -54,7 +54,9 @@ void EthashSealEngine::generateSeal(BlockInfo const& _bi)
 	m_farm.setWork(m_sealing);
 	m_farm.start(m_sealer);
 	m_farm.setWork(m_sealing);		// TODO: take out one before or one after...
-	Ethash::ensurePrecomputed((unsigned)_bi.number());
+	bytes shouldPrecompute = option("precomputeDAG");
+	if (!shouldPrecompute.empty() && shouldPrecompute[0] == 1)
+		Ethash::ensurePrecomputed((unsigned)_bi.number());
 }
 
 void EthashSealEngine::onSealGenerated(std::function<void(bytes const&)> const& _f)

libethereum/Client.cpp

@@ -443,6 +443,13 @@ void Client::setForceMining(bool _enable)
 		startMining();
 }
 
+void Client::setShouldPrecomputeDAG(bool _precompute)
+{
+	bytes trueBytes {1};
+	bytes falseBytes {0};
+	sealEngine()->setOption("precomputeDAG", _precompute ? trueBytes: falseBytes);
+}
+
 bool Client::isMining() const
 {
 	return Ethash::isWorking(m_sealEngine.get());

libethereum/Client.h

@@ -140,6 +140,8 @@ public:
 	bool turboMining() const { return m_turboMining; }
 	/// Enable/disable GPU mining.
 	void setTurboMining(bool _enable = true) { m_turboMining = _enable; if (isMining()) startMining(); }
+	/// Enable/disable precomputing of the DAG for next epoch
+	void setShouldPrecomputeDAG(bool _precompute);
 
 	/// Check to see if we'd mine on an apparently bad chain.
 	bool mineOnBadChain() const { return m_mineOnBadChain; }