Add --exit-new-epoch option (PR ethereum-mining#2367)

RTX 3000 must apply oc after DAG generation.
This option allows easier scripting because now scripts can know there is new epoch when ethminer exit.

ethminer/main.cpp

@@ -55,6 +55,7 @@ using namespace dev::eth;
 // Global vars
 bool g_running = false;
 bool g_exitOnError = false;  // Whether or not ethminer should exit on mining threads errors
+bool g_exitOnNewEpoch = false;  // Exit on new epoch
 
 condition_variable g_shouldstop;
 boost::asio::io_service g_io_service;  // The IO service itself
@@ -272,6 +273,8 @@ class MinerCLI
 
         app.add_flag("--exit", g_exitOnError, "");
 
+        app.add_flag("--exit-new-epoch", g_exitOnNewEpoch, "");
+
         vector<string> pools;
         app.add_option("-P,--pool", pools, "");
 
@@ -1009,6 +1012,8 @@ class MinerCLI
                  << "                        2 As 1 plus monitor power drain" << endl
                  << "    --exit              FLAG Stop ethminer whenever an error is encountered"
                  << endl
+                 << "    --exit-new-epoch    FLAG Stop ethminer when epoch changes"
+                 << endl
                  << "    --ergodicity        INT[0 .. 2] Default = 0" << endl
                  << "                        Sets how ethminer chooses the nonces segments to"
                  << endl

libethash-cuda/CUDAMiner.cpp

@@ -179,7 +179,9 @@ bool CUDAMiner::initEpoch_internal()
                 << m_deviceDescriptor.uniqueId;
         cudalog << "Mining suspended ...";
         pause(MinerPauseEnum::PauseDueToInitEpochError);
-        retVar = true;
+        string _what = "GPU error when generating DAG!";
+        throw std::runtime_error(_what);
+        retVar = false;
     }
 
     return retVar;
@@ -214,6 +216,11 @@ void CUDAMiner::workLoop()
             // Epoch change ?
             if (current.epoch != w.epoch)
             {
+                if (current.epoch != -1 && g_exitOnNewEpoch)
+                {
+                    std::cerr << "Epoch change, miner exit!" << std::endl;
+                    raise(SIGTERM);
+                }
                 if (!initEpoch())
                     break;  // This will simply exit the thread
 

libethash-cuda/CUDAMiner.h

@@ -25,6 +25,8 @@ along with ethminer.  If not, see <http://www.gnu.org/licenses/>.
 
 #include <functional>
 
+extern bool g_exitOnNewEpoch;
+
 namespace dev
 {
 namespace eth