FAQ (Frequently asked questions)

Q Why can't I install BenchmarkDotNet in Visual Studio 2010/2012/2013?

A BenchmarkDotNet requires NuGet 3.x+ and can't be installed in old versions of Visual Studio which use NuGet 2.x. Consider to use Visual Studio 2015/2017 or Rider. See also: BenchmarkDotNet#237, roslyn#12780.
Q Why can't I install BenchmarkDotNet in a new .NET Core Console App in Visual Studio 2017?

A BenchmarkDotNet supports only netcoreapp2.0+. Some old Visual Studio 2017 can create a new application which targets netcoreapp1.0. You should upgrade it up to 2.0. If you want to target netcoreapp1.0 in your main assembly, it's recommended to create a separated project for benchmarks.
Q I created a new .NET Core Console App in Visual Studio 2017. Now I want to run my code on CoreCLR, full .NET Framework, and Mono. How can I do it?

A Use the following lines in your .csproj file:
```
<TargetFrameworks>netcoreapp2.0;net46</TargetFrameworks>
<PlatformTarget>AnyCPU</PlatformTarget>
```
And mark your benchmark class with the following attributes:
```
[CoreJob, ClrJob, MonoJob]
```
Q My source code targets old versions of .NET Framework or .NET Core, but BenchmarkDotNet requires net461 and netcoreapp2.0. How can I run benchmarks in this case?

A It's a good practice to introduce an additional console application (e.g. MyAwesomeLibrary.Benchmarks) which will depend on your code and BenchmarkDotNet. Due to the fact that users usually run benchmarks in a develop environment and don't distribute benchmarks for users, it shouldn't be a problem.
Q I wrote a small benchmark, but BenchmarkDotNet requires a lot of time for time measurements. How can I reduce this time?

A By default, BenchmarkDotNet automatically chooses a number of iterations which allows achieving the best precision. If you don't need such level of precision and just want to have a quick way to get approximated results, you can specify all parameters manually. For example, you can use the SimpleJob or ShortRunJob attributes:
```
[SimpleJob(launchCount: 1, warmupCount: 3, iterationCount: 5, invocationCount:100, id: "QuickJob")]
[ShortRunJob]
```
Q My benchmark unexpectedly stopped and I saw the information about error code. What can I do?

A BenchmarkDotNet generates, builds and runs new process for every benchmark. This behavior is sometimes interpreted by anti-virus as dangerous, and the process is killed. Use EnvironmentAnalyser to detect antivirus software and configure your benchmark to use InProcessToolchain.
Q Can I run benchmark on the virtual machine?

A Yes, of course. However, it can affect results because of the shared, physical machine, virtualization process and incorrect Stopwatch.Frequency. If you are unsure whether an application is running on virtual environment, use EnvironmentAnalyser to detect VM hypervisor.

Q I have failed to run my benchmarks, I am getting following errors about non-optimized dll. What can I do?

Assembly BenchmarkDotNet.Samples which defines benchmarks references non-optimized BenchmarkDotNet
        If you own this dependency, please, build it in RELEASE.
        If you don't, you can create custom config with DontFailOnError to disable our custom policy and allow this b
Assembly BenchmarkDotNet.Samples which defines benchmarks is non-optimized
Benchmark was built without optimization enabled (most probably a DEBUG configuration). Please, build it in RELEASE.

A You should always run your benchmarks in RELEASE mode with optimizations enabled (default setting for RELEASE). However if you have to use non-optimized 3rd party assembly you have to create custom config to disable our default policy.

public class AllowNonOptimized : ManualConfig
{
    public AllowNonOptimized()
    {
        Add(JitOptimizationsValidator.DontFailOnError); // ALLOW NON-OPTIMIZED DLLS

        Add(DefaultConfig.Instance.GetLoggers().ToArray()); // manual config has no loggers by default
        Add(DefaultConfig.Instance.GetExporters().ToArray()); // manual config has no exporters by default
        Add(DefaultConfig.Instance.GetColumnProviders().ToArray()); // manual config has no columns by default
    }
}

Q I have failed to run my benchmarks from LINQPad. How can I fix this problem?
```
Assembly LINQPadQuery which defines benchmarks references non-optimized LINQPad
Assembly LINQPadQuery which defines benchmarks is non-optimized
Benchmark was built without optimization enabled (most probably a DEBUG configuration). Please, build it in RELEASE.
```
A You need to make sure that you are using AnyCPU 5.22.05+ build of LINQPad with optimizations enabled. To enable the optimizations you need to go to Preferences -> Query and select compile with /optimize+
Q I'm trying to use RPlotExporter but there are no any images in the results folder

A Try to specify R_LIBS_USER (e.g. R_LIBS_USER=/usr/local/lib/R/ on Linux/macOS, see also: #692)
Q My benchmark failed with OutOfMemoryException. How can I fix this problem?

A BenchmarkDotNet continues to run additional iterations until desired accuracy level is achieved. It's possible only if the benchmark method doesn't have any side-effects. If your benchmark allocates memory and keeps it alive, you are creating a memory leak.

You should redesign your benchmark and remove the side-effects. You can use OperationsPerInvoke, IterationSetup and IterationCleanup to do that.

An example:
```
public class OOM
{
    private StringBuilder buffer = new StringBuilder();

    [Benchmark]
    public void HasSideEffects()
    {
        // This method is growing the buffer to infinity
        // because it's executed millions of times
        buffer.Append('a');
    }

    [Benchmark(OperationsPerInvoke = 16)]
    public void HasNoSideEffects()
    {
        buffer.Clear();

        for (int i = 0; i < 1024; i++)
            buffer.Append('a');
    }
}
```

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FAQ (Frequently asked questions)