Minor optimization and cleanup

- Delete unnecessarily maintained variable
- Allow the compiler the option to inline time
  critical method.

Author: jean-m-cyr

libethcore/Miner.cpp

@@ -33,19 +33,6 @@ bool Miner::s_exit = false;
 
 bool Miner::s_noeval = false;
 
-void Miner::updateHashRate(uint64_t n)
-{
-    m_hashCounter = n;
-    std::chrono::steady_clock::time_point t = std::chrono::steady_clock::now();
-    float us = float(std::chrono::duration_cast<std::chrono::microseconds>(t - m_hashTime).count());
-    m_hashTime = t;
-
-    float hr = 0;
-    if (us)
-        hr = float(m_hashCounter) / (us / 1000000.0);
-    m_hashRate.store(hr, std::memory_order_relaxed);
-}
-
 std::ostream& operator<<(std::ostream& os, HwMonitor _hw)
 {
     os << _hw.tempC << "C " << _hw.fanP << "%";

libethcore/Miner.h

@@ -286,7 +286,18 @@ class Miner : public Worker
         return m_work;
     }
 
-    void updateHashRate(uint64_t _n);
+    inline void updateHashRate(uint64_t _n)
+    {
+        using namespace std::chrono;
+        steady_clock::time_point t = steady_clock::now();
+        auto us = duration_cast<microseconds>(t - m_hashTime).count();
+        m_hashTime = t;
+
+        float hr = 0.0;
+        if (us)
+            hr = (float(_n) * 1.0e6f) / us;
+        m_hashRate.store(hr, std::memory_order_relaxed);
+    }
 
     static unsigned s_dagLoadMode;
     static unsigned s_dagLoadIndex;
@@ -305,7 +316,6 @@ class Miner : public Worker
     WorkPackage m_work;
     mutable Mutex x_work;
     std::chrono::steady_clock::time_point m_hashTime = std::chrono::steady_clock::now();
-    uint64_t m_hashCounter = 0;
     std::atomic<float> m_hashRate = {0.0};
 };