Performance

The InterOp library is not optimized for speed. Nonetheless, the user should be aware of certain downsides to using the SWIG interface to C# (or any other language).

SWIG Binding Performance

The C# unit tests include a PerformanceTest.cs. This file shows three ways to simply sum all the focus scores for the first channel over >5 million entries.

The PerformanceTest.cs class demonstrates three different ways of summing focus scores:

2. Direct Call 1

The main loop in is C#

double sum = 0.0;
for(uint i=0;i<extraction_metric_set.size();i++)
sum += extraction_metric_set.at(i).focusScore(0);

3. Direct Call 2

The main loop in is C#

double sum = 0.0;
for(int lane = 1;lane <=8;lane++)
{
    for(int tile = 1;tile <=2000;tile++)
    {
        for(int cycle = 1;cycle <=318;cycle++)
        {

            extraction_metric metric = extraction_metric_set.GetMetric(lane, tile, cycle);
            sum += metric.focusScore(0);
        }
    }
}

1. Indirect Call

One loop in C++ One loop in C#

extraction_metric_set.copy_focus(focusVals, 0, (uint)focusVals.Length);
double sum = 0.0;
for(int i=0;i<focusVals.Length;i++) sum+=focusVals[i];

Results

The following table summarizes the results (the times are a single sample for illustrative purposes)

Test Name	Time (s)
Direct Call 1	38
Direct Call 2	45
Indirect Call	< 1

The results show that everytime we make a call from the native language to C++, we pay a hefty price. In many applications, this is a price we are willing to pay. However, for those applications where performance is a concern, it pays to add methods like copy_focus, which limit the number of times we have to jump between C# (or another language) and C++.