Why do trace and debug level logs give small size "Allocated" and "Mean" result in dotnetBenchMark?

Question

I am working on log severities with do.net 7 . I tried the test dotNetBenchMark library. I have questions about that result. As far as i know, debug and trace level logs have more info than other levels. if this true, i expect they should use more "allocated" than others. And why are they more faster "mean" than others? Or am i think wrong? I'll be glad if you help.

Thanks in advance.

I used nlog library. here is my nlog.config file:

<?xml version="1.0" ?>
<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <targets async = "true">
         <target name="console" xsi:type="Console" layout="${date:format=HH\:MM\:ss} ${logger} ${message}" />
    </targets>
    <rules>
       <logger enabled = "true" name="*"  minlevel="trace"  writeTo="console" />
   </rules>
</nlog>

And i have very very simple test case. "add 2 number and give result info". The code is below like that for all levels:

[Benchmark]
public void DoLogTrace()
{
    var number1 = 30;
    var number2 = 40;
    var number3 = number1 * number2;
    _logger.LogTrace("Method run is completed. The Result is {0}",number3);
}

[Benchmark]
public void DoLogDebug()
{
    var number1 = 30;
    var number2 = 40;
    var number3 = number1 * number2;
    _logger.LogDebug("Method run is completed. The Result is {0}",number3);
}

And I got the following result

Answer 1

There is no special optimization for Debug or Trace-events. LogTrace and LogError are just extension methods that calls the same underlying ILogger.Log -method.

The idea is that one only enables Trace or Debug, when needing to diagnose problems. When a LogLevel is disabled, then no output is generated and no allocations will be made.

The important part is how you build the _logger that you are benchmarking, which decides what Levels are enabled for logging together with their output-targets.

See also LoggerMessage.Define if you care about performance. And want to avoid the params-array-allocation introduced by using LogTrace or LogError -extension-methods.