App.config

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <configSections>
    <sectionGroup name="common">
      <section name="logging" type="Common.Logging.ConfigurationSectionHandler, Common.Logging" />
    </sectionGroup>
    <section name="nlog" type="NLog.Config.ConfigSectionHandler, NLog"/>
  </configSections>

  <common>
    <logging>
      <factoryAdapter type="Common.Logging.NLog.NLogLoggerFactoryAdapter, Common.Logging.NLog40">
        <arg key="configType" value="FILE" />
        <arg key="configFile" value="NLog.config" />
      </factoryAdapter>
    </logging>
  </common>
  
    <startup> 
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5.2" />
    </startup>
</configuration>

LogExecutionTimeAttribute.cs

using System;
using System.Diagnostics;
using System.Reflection;

using Common.Logging;

using PostSharp.Aspects;

namespace PostSharpInjectLogger
{
    [Serializable]
    public class LogExecutionTimeAttribute : OnMethodBoundaryAspect
    {
        [NonSerialized]
        public static Func<ILog> GetLogger;

        private string className;

        private string methodName;

        public LogExecutionTimeAttribute()
        {
            // Setting AspectPriority explicity avoids undeterministic behaviour 
            // when multiple aspects are applied, and avoids warning messages
            this.AspectPriority = 1;
        }

        /// <summary>
        /// Method executed at build time. Initializes the aspect instance. After the execution
        /// of <see cref="CompileTimeInitialize"/>, the aspect is serialized as a managed
        /// resource inside the transformed assembly, and de-serialized at runtime.
        /// </summary>
        /// <param name="method">Method to which the current aspect instance has been applied.</param>
        /// <param name="aspectInfo">Unused.</param>
        public override void CompileTimeInitialize(MethodBase method, AspectInfo aspectInfo)
        {
            this.className = method.DeclaringType.FullName;
            this.methodName = method.Name;
        }

        public override void OnEntry(MethodExecutionArgs args)
        {
            args.MethodExecutionTag = Stopwatch.StartNew();
            base.OnEntry(args);
        }

        public override void OnExit(MethodExecutionArgs args)
        {
            Stopwatch sw = (Stopwatch)args.MethodExecutionTag;
            sw.Stop();
            var logger = GetLogger();
            logger.DebugFormat(
                "{0}.{1} for Id={2} executed in {3} seconds.", 
                this.className, 
                this.methodName, 
                args.Arguments[0],
                sw.ElapsedMilliseconds / 1000.0);
            base.OnExit(args);
        }
    }
}

LogFileLogger.cs

using Common.Logging;

namespace PostSharpInjectLogger
{
    /// <summary>
    /// The base logger.
    /// </summary>
    public class LogFileLogger
    {
        public LogFileLogger(string runId)
        {
            NLog.MappedDiagnosticsContext.Set("RunId", runId);
            this.LogInstance = LogManager.GetLogger("FileLogger");
        }

        public ILog LogInstance { get; set; }
    }
}

NLog.config

<?xml version="1.0" encoding="utf-8" ?>
<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="http://www.nlog-project.org/schemas/NLog.xsd NLog.xsd"
      autoReload="true"
      throwExceptions="false"
      internalLogLevel="Off" internalLogFile="nlog-internal.log">

  <targets>
    <target xsi:type="File" 
            name="FileLogger" 
            fileName="${basedir}/logfile_${mdc:item=RunId}.log" 
            header="Time,RunId,ThreadId,Counter" 
            layout="${message}" 
            deleteOldFileOnStartup="true"/>
  </targets>

  <rules>
    <logger name="FileLogger" minlevel="Debug" writeTo="FileLogger" />
  </rules>
</nlog>

packages.config

<?xml version="1.0" encoding="utf-8"?>
<packages>
  <package id="Common.Logging" version="3.3.1" targetFramework="net452" />
  <package id="Common.Logging.Core" version="3.3.1" targetFramework="net452" />
  <package id="Common.Logging.NLog40" version="3.3.1" targetFramework="net452" />
  <package id="NLog" version="4.3.7" targetFramework="net452" />
  <package id="NLog.Config" version="4.3.7" targetFramework="net452" />
  <package id="NLog.Schema" version="4.3.7" targetFramework="net452" />
  <package id="PostSharp" version="4.3.19" targetFramework="net452" />
</packages>

Program.cs

using System;
using System.Threading;
using System.Threading.Tasks;

namespace PostSharpInjectLogger
{
    class Program
    {
        [LogExecutionTime]
        private static void DoTask(int id, Random rand)
        {
            Thread.Sleep(rand.Next(0, 100));
        }

        private static void HelloTask(int id)
        {
            var log = new LogFileLogger(id.ToString()).LogInstance;
            LogExecutionTimeAttribute.GetLogger = () => log;

            var rand = new Random(id);
            for (int i = 0; i < 100; i++)
            {
                DoTask(id, rand);
            }
        }

        static void Main(string[] args)
        {
            Task t1 = Task.Factory.StartNew(() => HelloTask(1), TaskCreationOptions.LongRunning);
            Task t2 = Task.Factory.StartNew(() => HelloTask(2), TaskCreationOptions.LongRunning);
            Task t3 = Task.Factory.StartNew(() => HelloTask(3), TaskCreationOptions.LongRunning);
            Task.WaitAll(t1, t2, t3);
        }
    }
}