Fix randomness error in Handler benchmark

src/test/rpc/Handler_test.cpp

@@ -41,26 +41,25 @@ class Handler_test : public beast::unit_test::suite
     time(std::size_t n, auto f, auto prng)
     {
         assert(n > 0);
-        // Prepare randomness cache away from performance measurements
-        std::vector<decltype(prng())> randomness;
-        randomness.reserve(n + 6);
-        for (std::size_t i = 0; i < n; i += 6)
-        {
-            randomness.push_back(prng());
-        }
-
         double sum = 0;
         double sum_squared = 0;
         std::size_t j = 0;
         while (j < n)
         {
+            // Generate 20 inputs upfront, separated from the inner loop
+            std::array<decltype(prng()), 20> inputs = {};
+            for (auto& i : inputs)
+            {
+                i = prng();
+            }
+
             // Take 20 samples and throw away 7 from each end, using middle 6
             std::array<long, 20> samples = {};
-            for (auto& s : samples)
+            for (std::size_t k = 0; k < 20; ++k)
             {
-                auto start = std::chrono::high_resolution_clock::now();
-                f(randomness[j]);
-                s = (std::chrono::high_resolution_clock::now() - start).count();
+                auto start = std::chrono::steady_clock::now();
+                f(inputs[k]);
+                samples[k] = (std::chrono::steady_clock::now() - start).count();
             }
 
             std::sort(samples.begin(), samples.end());