Performance benchmark references

[MikeAlhayek]

Use string interpolation when concatenation few strings.

A benchmark on a medium size string

That output of the following benchmark

[MemoryDiagnoser]
public class MediumStringConcatenationBenchmarks
{
    private const string Phrase1 = "In the vast expanse of the cosmos, stars dance in celestial choreography";
    private const string Phrase2 = "weaving tales of cosmic marvels, while on Earth, the tapestry of life unfolds";
    private const string Phrase3 = "intertwining moments of joy, sorrow, and discovery, echoing the symphony of existence itself.";
    private const string Separator = ", ";

    [Benchmark(Baseline = true)]
    public string StringConcatenation()
    {
        var result = string.Empty;

        result += Phrase1;
        result += Separator;
        result += Phrase2;
        result += Separator;
        result += Phrase3;

        return result;
    }

    [Benchmark]
    public string StringConcatenationOneLine()
    {
        var result = Phrase1 + Separator + Phrase2 + Separator + Phrase3;

        return result;
    }

    [Benchmark]
    public string StringInterpolation()
    {
        var result = $"{Phrase1}{Separator}{Phrase2}{Separator}{Phrase3}";

        return result;
    }

    [Benchmark]
    public string StringBuilder()
    {
        var builder = new StringBuilder();
        builder.Append(Phrase1);
        builder.Append(Separator);
        builder.Append(Phrase2);
        builder.Append(Separator);
        builder.Append(Phrase3);

        return builder.ToString();
    }
}

But, when we are doing many concatenations, the results are not as good.

Here is the benchmark I used

[MemoryDiagnoser]
public class SmallStringConcatenationBenchmarks
{
    private const string Phrase1 = "One";
    private const string Phrase2 = "Two";
    private const string Phrase3 = "Three";
    private const string Phrase4 = "Four";
    private const string Phrase5 = "Five";
    private const string Phrase6 = "Six";
    private const string Phrase7 = "Seven";
    private const string Phrase8 = "Eight";
    private const string Phrase9 = "Nine";
    private const string Phrase10 = "Ten";
    private const char Separator = ' ';

    [Benchmark(Baseline = true)]
    public string StringConcatenation()
    {
        var result = string.Empty;

        result += Phrase1;
        result += Separator;
        result += Phrase2;
        result += Separator;
        result += Phrase3;
        result += Separator;
        result += Phrase4;
        result += Separator;
        result += Phrase5;
        result += Separator;
        result += Phrase6;
        result += Separator;
        result += Phrase7;
        result += Separator;
        result += Phrase8;
        result += Separator;
        result += Phrase9;
        result += Separator;
        result += Phrase10;

        return result;
    }

    [Benchmark]
    public string StringConcatenationOneLine()
    {
        var result = Phrase1 + Separator
            + Phrase2 + Separator
            + Phrase3 + Separator
            + Phrase3 + Separator
            + Phrase4 + Separator
            + Phrase5 + Separator
            + Phrase6 + Separator
            + Phrase7 + Separator
            + Phrase8 + Separator
            + Phrase9 + Separator
            + Phrase10;

        return result;
    }

    [Benchmark]
    public string StringInterpolation()
    {
        var result = $"{Phrase1}{Separator}{Phrase2}{Separator}{Phrase3}{Separator}{Phrase4}{Separator}{Phrase5}{Separator}{Phrase6}{Separator}{Phrase7}{Separator}{Phrase8}{Separator}{Phrase9}{Separator}{Phrase10}";

        return result;
    }

    [Benchmark]
    public string StringBuilder()
    {
        var builder = new StringBuilder();
        builder.Append(Phrase1);
        builder.Append(Separator);
        builder.Append(Phrase2);
        builder.Append(Separator);
        builder.Append(Phrase3);
        builder.Append(Separator);
        builder.Append(Phrase4);
        builder.Append(Separator);
        builder.Append(Phrase5);
        builder.Append(Separator);
        builder.Append(Phrase6);
        builder.Append(Separator);
        builder.Append(Phrase7);
        builder.Append(Separator);
        builder.Append(Phrase8);
        builder.Append(Separator);
        builder.Append(Phrase9);
        builder.Append(Separator);
        builder.Append(Phrase10);

        return builder.ToString();
    }
}

/cc @deanmarcussen

[MikeAlhayek]

Use IEnumerable when possible and avoid having to convert with .ToList() or .ToArray() if possible.

Using List is faster but comes at the cost of allocation more as you expected. I'll modify the code to no use the list.

[MikeAlhayek]

Use .ToArray() over .ToList() when possible

As you can see from the benchmark below, .ToArray() is slightly faster that .ToList() with slightly less allocations.

@sebastienros we had the opposite in mind.

[MikeAlhayek]

Creating the same object very often can be costly.

In places like INavigationProvider where we call the handler on every single request, creating the same object over and over can be expensive.

As simple as one constant variable saves 12 mb in memory allocation over 100k requests.

For example, the below AdminMenu class, we store the RouteValues in a const variable which is created only one during the entire life of the app. This object will be used by every single request (from any tenant). This small change will reduce lots of allocations over the life of the app. Make sure you do not store client specific data in a const variable!

public class AdminMenu : INavigationProvider
{
    private static readonly RouteValueDictionary _routeValues = new()
    {
        { "area", "OrchardCore.Settings" },
        { "groupId", AdminSiteSettingsDisplayDriver.GroupId },
    };

    protected readonly IStringLocalizer S;

    public AdminMenu(IStringLocalizer<AdminMenu> stringLocalizer)
    {
        S = stringLocalizer;
    }

    public Task BuildNavigationAsync(string name, NavigationBuilder builder)
    {
        if (!NavigationHelper.IsAdminMenu(name))
        {
            return Task.CompletedTask;
        }

        builder
            .Add(S["Configuration"], configuration => configuration
                .Add(S["Settings"], settings => settings
                    .Add(S["Admin"], S["Admin"].PrefixPosition(), admin => admin
                        .AddClass("admin")
                        .Id("admin")
                        .Action("Index", "Admin", _routeValues)
                        .Permission(PermissionsAdminSettings.ManageAdminSettings)
                        .LocalNav()
                    )
                )
            );

        return Task.CompletedTask;
    }
}