Auto merge of #2227 - str4d:2074-ignore-virtual-cores, r=str4d

Use real number of cores, ignore virtual cores

Cherry-picked from the following upstream PRs:

- bitcoin/bitcoin#6361
- bitcoin/bitcoin#6370

Part of #2074.

src/chainparams.cpp

@@ -59,7 +59,6 @@ public:
         pchMessageStart[3] = 0x64;
         vAlertPubKey = ParseHex("04b7ecf0baa90495ceb4e4090f6b2fd37eec1e9c85fac68a487f3ce11589692e4a317479316ee814e066638e1db54e37a10689b70286e6315b1087b6615d179264");
         nDefaultPort = 8233;
-        nMinerThreads = 0;
         nMaxTipAge = 24 * 60 * 60;
         nPruneAfterHeight = 100000;
         const size_t N = 200, K = 9;
@@ -219,7 +218,6 @@ public:
         pchMessageStart[3] = 0xbf;
         vAlertPubKey = ParseHex("044e7a1553392325c871c5ace5d6ad73501c66f4c185d6b0453cf45dec5a1322e705c672ac1a27ef7cdaf588c10effdf50ed5f95f85f2f54a5f6159fca394ed0c6");
         nDefaultPort = 18233;
-        nMinerThreads = 0;
         nPruneAfterHeight = 1000;
 
         //! Modify the testnet genesis block so the timestamp is valid for a later start.
@@ -308,7 +306,6 @@ public:
         pchMessageStart[1] = 0xe8;
         pchMessageStart[2] = 0x3f;
         pchMessageStart[3] = 0x5f;
-        nMinerThreads = 1;
         nMaxTipAge = 24 * 60 * 60;
         const size_t N = 48, K = 5;
         BOOST_STATIC_ASSERT(equihash_parameters_acceptable(N, K));

src/chainparams.h

@@ -53,8 +53,6 @@ public:
     const std::vector<unsigned char>& AlertKey() const { return vAlertPubKey; }
     int GetDefaultPort() const { return nDefaultPort; }
 
-    /** Used if GenerateBitcoins is called with a negative number of threads */
-    int DefaultMinerThreads() const { return nMinerThreads; }
     const CBlock& GenesisBlock() const { return genesis; }
     /** Make miner wait to have peers to avoid wasting work */
     bool MiningRequiresPeers() const { return fMiningRequiresPeers; }
@@ -91,7 +89,6 @@ protected:
     //! Raw pub key bytes for the broadcast alert signing key.
     std::vector<unsigned char> vAlertPubKey;
     int nDefaultPort = 0;
-    int nMinerThreads = 0;
     long nMaxTipAge = 0;
     uint64_t nPruneAfterHeight = 0;
     unsigned int nEquihashN = 0;

src/init.cpp

@@ -351,7 +351,7 @@ std::string HelpMessage(HelpMessageMode mode)
     strUsage += HelpMessageOpt("-loadblock=<file>", _("Imports blocks from external blk000??.dat file") + " " + _("on startup"));
     strUsage += HelpMessageOpt("-maxorphantx=<n>", strprintf(_("Keep at most <n> unconnectable transactions in memory (default: %u)"), DEFAULT_MAX_ORPHAN_TRANSACTIONS));
     strUsage += HelpMessageOpt("-par=<n>", strprintf(_("Set the number of script verification threads (%u to %d, 0 = auto, <0 = leave that many cores free, default: %d)"),
-        -(int)boost::thread::hardware_concurrency(), MAX_SCRIPTCHECK_THREADS, DEFAULT_SCRIPTCHECK_THREADS));
+        -GetNumCores(), MAX_SCRIPTCHECK_THREADS, DEFAULT_SCRIPTCHECK_THREADS));
 #ifndef WIN32
     strUsage += HelpMessageOpt("-pid=<file>", strprintf(_("Specify pid file (default: %s)"), "zcashd.pid"));
 #endif
@@ -927,7 +927,7 @@ bool AppInit2(boost::thread_group& threadGroup, CScheduler& scheduler)
     // -par=0 means autodetect, but nScriptCheckThreads==0 means no concurrency
     nScriptCheckThreads = GetArg("-par", DEFAULT_SCRIPTCHECK_THREADS);
     if (nScriptCheckThreads <= 0)
-        nScriptCheckThreads += boost::thread::hardware_concurrency();
+        nScriptCheckThreads += GetNumCores();
     if (nScriptCheckThreads <= 1)
         nScriptCheckThreads = 0;
     else if (nScriptCheckThreads > MAX_SCRIPTCHECK_THREADS)

src/metrics.cpp

@@ -46,6 +46,12 @@ bool AtomicTimer::running()
     return threads > 0;
 }
 
+uint64_t AtomicTimer::threadCount()
+{
+    std::unique_lock<std::mutex> lock(mtx);
+    return threads;
+}
+
 double AtomicTimer::rate(const AtomicCounter& count)
 {
     std::unique_lock<std::mutex> lock(mtx);
@@ -192,15 +198,8 @@ int printMiningStatus(bool mining)
     int lines = 1;
 
     if (mining) {
-        int nThreads = GetArg("-genproclimit", 1);
-        if (nThreads < 0) {
-            // In regtest threads defaults to 1
-            if (Params().DefaultMinerThreads())
-                nThreads = Params().DefaultMinerThreads();
-            else
-                nThreads = boost::thread::hardware_concurrency();
-        }
-        if (miningTimer.running()) {
+        auto nThreads = miningTimer.threadCount();
+        if (nThreads > 0) {
             std::cout << strprintf(_("You are mining with the %s solver on %d threads."),
                                    GetArg("-equihashsolver", "default"), nThreads) << std::endl;
         } else {

src/metrics.h

@@ -49,6 +49,8 @@ public:
 
     bool running();
 
+    uint64_t threadCount();
+
     double rate(const AtomicCounter& count);
 };
 

src/miner.cpp

@@ -748,13 +748,8 @@ void GenerateBitcoins(bool fGenerate, int nThreads)
 {
     static boost::thread_group* minerThreads = NULL;
 
-    if (nThreads < 0) {
-        // In regtest threads defaults to 1
-        if (Params().DefaultMinerThreads())
-            nThreads = Params().DefaultMinerThreads();
-        else
-            nThreads = boost::thread::hardware_concurrency();
-    }
+    if (nThreads < 0)
+        nThreads = GetNumCores();
 
     if (minerThreads != NULL)
     {

src/util.cpp

@@ -908,3 +908,13 @@ std::string LicenseInfo()
            FormatParagraph(_("This product includes software developed by the OpenSSL Project for use in the OpenSSL Toolkit <https://www.openssl.org/> and cryptographic software written by Eric Young and UPnP software written by Thomas Bernard.")) +
            "\n";
 }
+
+int GetNumCores()
+{
+#if BOOST_VERSION >= 105600
+    return boost::thread::physical_concurrency();
+#else // Must fall back to hardware_concurrency, which unfortunately counts virtual cores
+    return boost::thread::hardware_concurrency();
+#endif
+}
+

src/util.h

@@ -219,6 +219,13 @@ std::string HelpMessageGroup(const std::string& message);
  */
 std::string HelpMessageOpt(const std::string& option, const std::string& message);
 
+/**
+ * Return the number of physical cores available on the current system.
+ * @note This does not count virtual cores, such as those provided by HyperThreading
+ * when boost is newer than 1.56.
+ */
+int GetNumCores();
+
 void SetThreadPriority(int nPriority);
 void RenameThread(const char* name);