From 5b73ce1428d32a2c817562b3447840dc6d0e71b8 Mon Sep 17 00:00:00 2001
From: Joel Liang <joel.liang@arm.com>
Date: Tue, 21 Nov 2017 16:50:53 +0800
Subject: APPBROWSER-313: medium value and relative standard deviation

Calculate the median value and relative standard deviation for better performance comparison.

Change-Id: I433baa0b030f988d661777b2cbf8bf10c70f39d4
Reviewed-on: https://eu-gerrit-1.euhpc.arm.com/111638
Tested-by: BSG Visual Compute Jenkins server to access repositories on http://mpd-gerrit.cambridge.arm.com <bsgcomp@arm.com>
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
Reviewed-by: Anthony Barbier <anthony.barbier@arm.com>
---
 tests/framework/instruments/Measurement.h  | 50 ++++++++++++++++++++++++++++++
 tests/framework/printers/PrettyPrinter.cpp | 20 +++++++++++-
 2 files changed, 69 insertions(+), 1 deletion(-)

(limited to 'tests/framework')

diff --git a/tests/framework/instruments/Measurement.h b/tests/framework/instruments/Measurement.h
index 8a1ec9cb14..9fb75d7b99 100644
--- a/tests/framework/instruments/Measurement.h
+++ b/tests/framework/instruments/Measurement.h
@@ -92,6 +92,44 @@ struct Measurement
             return b;
         }
 
+        /** Subtract with another value and return the result
+         *
+         * @param[in] b Other value
+         *
+         * @return Result of the stored value - b
+         */
+        Value operator-(Value b) const
+        {
+            if(is_floating_point)
+            {
+                b.v.floating_point -= v.floating_point;
+            }
+            else
+            {
+                b.v.integer -= v.integer;
+            }
+            return b;
+        }
+
+        /** Multiple with another value and return the result
+         *
+         * @param[in] b Other value
+         *
+         * @return Result of the stored value * b
+         */
+        Value operator*(Value b) const
+        {
+            if(is_floating_point)
+            {
+                b.v.floating_point *= v.floating_point;
+            }
+            else
+            {
+                b.v.integer *= v.integer;
+            }
+            return b;
+        }
+
         /** Return the stored value divided by an integer.
          *
          * @param[in] b Integer to divide the value by.
@@ -149,6 +187,18 @@ struct Measurement
             }
         }
 
+        static double relative_standard_deviation(const Value &variance, const Value &mean)
+        {
+            if(variance.is_floating_point)
+            {
+                return 100.0 * sqrt(variance.v.floating_point) / mean.v.floating_point;
+            }
+            else
+            {
+                return 100.0 * sqrt(static_cast<double>(variance.v.integer)) / mean.v.integer;
+            }
+        }
+
         /** Stored value */
         union
             {
diff --git a/tests/framework/printers/PrettyPrinter.cpp b/tests/framework/printers/PrettyPrinter.cpp
index a2ce821f6b..085b2b900d 100644
--- a/tests/framework/printers/PrettyPrinter.cpp
+++ b/tests/framework/printers/PrettyPrinter.cpp
@@ -135,6 +135,22 @@ void PrettyPrinter::print_measurements(const Profiler::MeasurementsMap &measurem
         const auto         minmax_values = std::minmax_element(instrument.second.begin(), instrument.second.end(), cmp_measurements);
         Measurement::Value sum_values    = std::accumulate(instrument.second.begin(), instrument.second.end(), Measurement::Value(minmax_values.first->value().is_floating_point), add_measurements);
 
+        // Calculate the median value
+        auto measurements = instrument.second;
+        std::nth_element(measurements.begin(), measurements.begin() + (num_values / 2), measurements.end(), cmp_measurements);
+        const auto median_value = measurements[num_values / 2];
+
+        // Calculate the relative standard deviation
+        auto                            mean_value = sum_values / num_values;
+        std::vector<Measurement::Value> diff(measurements.size(), minmax_values.first->value().is_floating_point);
+        std::transform(measurements.begin(), measurements.end(), diff.begin(), [mean_value](const Measurement & x)
+        {
+            return x.value() - mean_value;
+        });
+        auto sq_sum   = std::inner_product(diff.begin(), diff.end(), diff.begin(), Measurement::Value(minmax_values.first->value().is_floating_point));
+        auto variance = sq_sum / measurements.size();
+        auto rsd      = Measurement::Value::relative_standard_deviation(variance, mean_value);
+
         if(num_values > 2)
         {
             sum_values -= minmax_values.first->value() + minmax_values.second->value();
@@ -142,7 +158,9 @@ void PrettyPrinter::print_measurements(const Profiler::MeasurementsMap &measurem
         }
 
         *_stream << "    ";
-        *_stream << "AVG=" << (sum_values / num_values) << " " << minmax_values.second->unit() << ",";
+        *_stream << "MEDIAN=" << median_value.value() << " " << median_value.unit() << ", ";
+        *_stream << "AVG=" << (sum_values / num_values) << " " << minmax_values.second->unit() << ", ";
+        *_stream << "STDDEV=" << arithmetic_to_string(rsd, 2) << " %, ";
         if(num_values > 1)
         {
             *_stream << "MIN=" << *minmax_values.first << ", ";
-- 
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