| ## Micro Benchmarks |
|
|
| This folder contains micro benchmarks that test the performance of PowerShell Engine. |
|
|
| ### Requirement |
|
|
| 1. A good suite of benchmarks |
| Something that measures only the thing that we are interested in and _produces accurate, stable and repeatable results_. |
| 2. A set of machine with the same configurations. |
| 3. Automation for regression detection. |
|
|
| ### Design Decision |
|
|
| 1. This project is internal visible to `System.Management.Automation`. |
| We want to be able to target some internal APIs to get measurements on specific scoped scenarios, |
| such as measuring the time to compile AST to a delegate by the compiler. |
| 2. This project makes `ProjectReference` to other PowerShell assemblies. |
| This makes it easy to run benchmarks with the changes made in the codebase. |
| To run benchmarks with a specific version of PowerShell, |
| just replace the `ProjectReference` with a `PackageReference` to the `Microsoft.PowerShell.SDK` NuGet package of the corresponding version. |
|
|
| ### Quick Start |
|
|
| You can run the benchmarks directly using `dotnet run` in this directory: |
| 1. To run the benchmarks in Interactive Mode, where you will be asked which benchmark(s) to run: |
| ``` |
| dotnet run -c Release -f net6.0 |
| ``` |
|
|
| 2. To list all available benchmarks ([read more](https://github.com/dotnet/performance/blob/main/docs/benchmarkdotnet.md#Listing-the-Benchmarks)): |
| ``` |
| dotnet run -c Release -f net6.0 --list [flat/tree] |
| ``` |
|
|
| 3. To filter the benchmarks using a glob pattern applied to `namespace.typeName.methodName` ([read more](https://github.com/dotnet/performance/blob/main/docs/benchmarkdotnet.md#Filtering-the-Benchmarks)]): |
| ``` |
| dotnet run -c Release -f net6.0 --filter *script* --list flat |
| ``` |
|
|
| 4. To profile the benchmarked code and produce an ETW Trace file ([read more](https://github.com/dotnet/performance/blob/main/docs/benchmarkdotnet.md#Profiling)) |
| ``` |
| dotnet run -c Release -f net6.0 --filter *script* --profiler ETW |
| ``` |
|
|
| You can also use the function `Start-Benchmarking` from the module [`perf.psm1`](../perf.psm1) to run the benchmarks: |
| ```powershell |
| Start-Benchmarking [-TargetFramework <string>] [-List <string>] [-Filter <string[]>] [-Artifacts <string>] [-KeepFiles] [<CommonParameters>] |
| |
| Start-Benchmarking [-TargetPSVersion <string>] [-Filter <string[]>] [-Artifacts <string>] [-KeepFiles] [<CommonParameters>] |
| |
| Start-Benchmarking -Runtime <string[]> [-Filter <string[]>] [-Artifacts <string>] [-KeepFiles] [<CommonParameters>] |
| ``` |
| Run `Get-Help Start-Benchmarking -Full` to see the description of each parameter. |
|
|
| ### Regression Detection |
|
|
| We use the tool [`ResultsComparer`](../dotnet-tools/ResultsComparer) to compare the provided benchmark results. |
| See the [README.md](../dotnet-tools/ResultsComparer/README.md) for `ResultsComparer` for more details. |
|
|
| The module `perf.psm1` also provides `Compare-BenchmarkResult` that wraps `ResultsComparer`. |
| Here is an example of using it: |
|
|
| ``` |
| ## Run benchmarks targeting the current code base |
| PS:1> Start-Benchmarking -Filter *script* -Artifacts C:\arena\tmp\BenchmarkDotNet.Artifacts\current\ |
| |
| ## Run benchmarks targeting the 7.1.3 version of PS package |
| PS:2> Start-Benchmarking -Filter *script* -Artifacts C:\arena\tmp\BenchmarkDotNet.Artifacts\7.1.3 -TargetPSVersion 7.1.3 |
| |
| ## Compare the results using 5% threshold |
| PS:3> Compare-BenchmarkResult -BaseResultPath C:\arena\tmp\BenchmarkDotNet.Artifacts\7.1.3\ -DiffResultPath C:\arena\tmp\BenchmarkDotNet.Artifacts\current\ -Threshold 1% |
| summary: |
| better: 4, geomean: 1.057 |
| total diff: 4 |
| |
| No Slower results for the provided threshold = 1% and noise filter = 0.3ns. |
| |
| | Faster | base/diff | Base Median (ns) | Diff Median (ns) | Modality| |
| | -------------------------------------------------------------------------------- | ---------:| ----------------:| ----------------:| --------:| |
| | Engine.Scripting.InvokeMethod(Script: "$fs=New-Object -ComObject scripting.files | 1.07 | 50635.77 | 47116.42 | | |
| | Engine.Scripting.InvokeMethod(Script: "$sh=New-Object -ComObject Shell.Applicati | 1.07 | 1063085.23 | 991602.08 | | |
| | Engine.Scripting.InvokeMethod(Script: "'String'.GetType()") | 1.06 | 1329.93 | 1252.51 | | |
| | Engine.Scripting.InvokeMethod(Script: "[System.IO.Path]::HasExtension('')") | 1.02 | 1322.04 | 1297.72 | | |
| |
| No file given |
| ``` |
|
|
| ## References |
|
|
| - [Getting started with BenchmarkDotNet](https://benchmarkdotnet.org/articles/guides/getting-started.html) |
| - [Micro-benchmark Design Guidelines](https://github.com/dotnet/performance/blob/main/docs/microbenchmark-design-guidelines.md) |
| - [Adam SITNIK: Powerful benchmarking in .NET](https://www.youtube.com/watch?v=pdcrSG4tOLI&t=351s) |
|
|
