BenchmarkDotNet v0.10.10

BenchmarkDotNet v0.10.10 has been released! This release includes many new features like Disassembly Diagnoser, ParamsSources, .NET Core x86 support, Environment variables, and more!


There are so many changes in this version! In this post, I’m going to tell you about the most useful features.

Disassembly Diagnoser

This feature by @adamsitnik allows looking at the assembly code of your methods. It really helps when you investigate some CPU-bound benchmarks. BenchmarkDotNet not only shows naive disasm, but it also prettify the listing can work with hardware counters:

You can find the full info in the Disassembling .NET Code with BenchmarkDotNet blog post by Adam Sitnik.

It turned out that this feature is useful for comparing assembly for different versions of .NET JIT-compilers. Check out a recent post from Microsoft .NET Blog by Joseph Tremoulet: RyuJIT Just-in-Time Compiler Optimization Enhancements. In this post, Joseph compares RyuJIT assembly code for .NET Core 2.0 RTM and .NET Core 2.1.0-preview1-25719-04.

It’s really great to see that BenchmarkDotNet helps to develop such products like .NET Core. By the way, the development process is also useful for BenchmarkDotNet. Here are some great bug reports by Joseph which were fixed by Adam: #535, #536, #559, #562.

Now BenchmarkDotNet can produce assembly for .NET Framework and .NET Core; Mono support is coming soon. Of course, we have also many additional feature requests: #543, #544, #545, #546, #560 (any help will be highly appreciated).


BenchmarkDotNet allows to parametrize your benchmark and run it against several parameter values. v0.10.9 supported only a constant set of parameters which should be declared inside the attribute;

[Params(100, 200)]
public int A { get; set; }

[Params(10, 20)]
public int B { get; set; }

It’s not always convenient, sometimes we need a way to define parameter values dynamically. Now you can do it!

public int A { get; set; } // property with public setter

public int B; // public field

public IEnumerable<int> ValuesForA => new[] { 100, 200 }; // public property

public static IEnumerable<int> ValuesForB() => new[] { 10, 20 }; // public static method

See also: #350, #571 and docs.

.NET Core x86 support

Since .NET Core 2.0, we can run it not only on x64, but also on x86. If we have both versions of runtime installed, we can try the same code on both platforms at the same time. Here is a config for you:

public class CustomPathsConfig : ManualConfig
    public CustomPathsConfig() 
        var dotnetCli32bit = NetCoreAppSettings
            .WithCustomDotNetCliPath(@"C:\Program Files (x86)\dotnet\dotnet.exe", "32 bit cli");

        var dotnetCli64bit = NetCoreAppSettings
            .WithCustomDotNetCliPath(@"C:\Program Files\dotnet\dotnet.exe", "64 bit cli");

        Add(Job.RyuJitX86.With(CsProjCoreToolchain.From(dotnetCli32bit)).WithId("32 bit cli"));
        Add(Job.RyuJitX64.With(CsProjCoreToolchain.From(dotnetCli64bit)).WithId("64 bit cli"));

See also: #310, #534 and docs.

Environment variables and Mono args

One of the keys features of BenchmarkDotNet is comparing different environments. And we add more and more options for you in each release. Now you can specify Mono arguments:

public class ConfigWithCustomArguments : ManualConfig
    public ConfigWithCustomArguments()
        // --optimize=MODE , -O=mode
        // MODE is a comma separated list of optimizations. They also allow
        // optimizations to be turned off by prefixing the optimization name with a minus sign.

        Add(Job.Mono.With(new[] { new MonoArgument("--optimize=inline") }).WithId("Inlining enabled"));
        Add(Job.Mono.With(new[] { new MonoArgument("--optimize=-inline") }).WithId("Inlining disabled"));

And environment variables:

public class ConfigWithCustomEnvVars : ManualConfig
    public ConfigWithCustomEnvVars()
        Add(Job.Core.WithId("Inlining enabled"));
            new[] { new EnvironmentVariable("COMPlus_JitNoInline", "1") })
            .WithId("Inlining disabled"));

You can find hundreds of runtime knobs here. Now it’s so easy to compare performance between different knobs values!

See also: #262 and docs.

Better environment description

When BenchmarkDotNet prints the summary about benchmarks, it always shows brief information about our environment. Now we can detect situation when you run a benchmark on a virtual machine (at least, in some cases) and print a warning about it (thanks @lukasz-pyrzyk; #167, #527). We support detecting HyperV, VirtualBox, VMware (Windows only for now).

Also now we support Windows 10 [1709, Fall Creators Update] and always print the revision number of Windows 10 version (like 10.0.15063.674 instead of 10.0.15063).


Of course, v0.10.10 includes not only new features but also additional sections in the documentation, bug fixes, build script improvements, internal refactoring. It’s not so exciting to write about such stuff in the release notes, but it’s also very important changes which improve the overall quality of the library.

Issues and Pull Requests

In the v0.10.10 scope, 34 issues were resolved and 18 pull requests were merged. This release includes 95 commits by 12 contributors:

Thank you very much!

Resolved Issues

  • #160 Make ClrMd Source diagnoser working with new ClrMD api
  • #167 Detect virtual machine environment
  • #262 Runtime knobs
  • #310 Support 32bit benchmarks for .NET Core
  • #350 ParamsSource
  • #437 Add DisassemblyDiagnoser for outputting disassembled JITed code
  • #466 MSBuild parameters are not passed to generated benchmark project
  • #495 Attributes put on base methods are not considered in derived class
  • #500 Borken compilation for net46 projects when .NET Framework 4.7 is installed
  • #505 JsonExporterBase doesn’t include MemoryDiagnoser stats in output
  • #511 [bug] Bug in GetTargetedMatchingMethod() logic
  • #513 IterationSetup not run in Job.InProcess
  • #516 Get a compilation error “CS1009: Unrecognized escape sequence” when using verbatim strings
  • #519 BenchmarkSwitcher.RunAllJoined throws InvalidOperationException
  • #526 Remove project.json support
  • #529 No namespace in export filenames can lead to data loss
  • #530 Build error on Appveyor with recent changes
  • #533 When I clone, build, and run BenchmarkDotNet.Samples I get an error
  • #534 Allow the users to compare 32 vs 64 RyuJit for .NET Core
  • #535 No way to set RuntimeFrameworkVersion in multiple-version config
  • #536 Strange disassembly ordering/truncation
  • #537 Can’t benchmark a netstandard2.0 project
  • #538 Duplicate using causing benchmark not to work
  • #539 Target .NET Core 2.0 to take advantage of the new APIs
  • #540 Artifacts for disassembler projects
  • #542 Problems with Disassembler + Job.Dry
  • #555 Test “CanDisassembleAllMethodCalls” fails on Ubuntu
  • #556 Table in report is broken in VSCode markdown viewer
  • #558 Warn the users when running Benchmarks from xUnit with shadow copy enabled
  • #559 DissassemblyDiagnoser jit/arch info seems to be wrong
  • #561 Strange behaviour when benchmark project is build in debug mode
  • #562 DisassemblyDiagnoser crashes on overloaded benchmark
  • #564 [Bug] Benchmarking a method doesn’t run global setup when filter is applied
  • #571 Allow users to use non compile-time constants as Parameters

Merged Pull Requests

  • #507 Fix a typo in
  • #508 Fixed some typos and grammar
  • #512 Warning about antivirus software after benchmark failure
  • #514 #495 - Unit test for reading attributes from the base class
  • #515 Fix #513 - IterationSetup not run in Job.InProcess
  • #518 Fixed information about MemoryDiagnoser
  • #520 XML Exporter documentation and samples
  • #525 adding validator for setup cleanup attributes
  • #527 Detecting virtual machine hypervisor, #167
  • #531 Remove –no-build argument for dotnet test & pack commands
  • #532 Fix type of local in EmitInvokeMultipleBody
  • #547 Fix markdown headers
  • #548 Fix condition in package reference list and update dotnet cli version from 1.0.4 to 2.0.0 for non-Windows system
  • #549 Project files cleanup
  • #552 Fix exporters to use fully qualified filenames
  • #563 Remove leading space character in a MD table row, #556
  • #565 Single point of full config creation
  • #569 Update cakebuild scripts