{"id":23084,"date":"2019-05-08T09:00:57","date_gmt":"2019-05-08T16:00:57","guid":{"rendered":"https:\/\/devblogs.microsoft.com\/dotnet\/?p=23084"},"modified":"2019-05-08T09:05:47","modified_gmt":"2019-05-08T16:05:47","slug":"introducing-diagnostics-improvements-in-net-core-3-0","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/dotnet\/introducing-diagnostics-improvements-in-net-core-3-0\/","title":{"rendered":"Introducing diagnostics improvements in .NET Core 3.0"},"content":{"rendered":"

In .NET Core 3.0, we are introducing a suite of tools that utilize new features in the .NET runtime that make it easier to diagnose and solve performance problems.<\/p>\n

These runtime features help you answer some common diagnostic questions you may have:<\/p>\n

    \n
  1. Is my application healthy?<\/li>\n
  2. Why does my application have anomalous behavior?<\/li>\n
  3. Why did my application crash?<\/li>\n<\/ol>\n

    Is my application healthy?<\/h3>\n

    Often times an application can slowly start leaking memory and eventually result in an out of memory exception. Other times, certain problematic code paths may result in a spike in CPU utilization. These are just some of the classes of problem you can pro-actively identify with metrics<\/strong>.<\/p>\n

    Metrics<\/h4>\n

    Metrics are a representation of data measures over intervals of time. Metrics (or time-series) data allow you to observe the state of your system at a high-level. Unlike the .NET Framework on Windows, .NET Core doesn\u2019t emit perf counters. Instead, we had introduced a new way of emitting metrics in .NET Core via the EventCounter<\/a> API.<\/p>\n

    EventCounters offer an improvement over Windows perf counters as these are now usable on all OSes where .NET Core is supported. Additionally, unlike perf counters, they are also usable in low privilege environments (like xcopy deployments). Unfortunately, the lack of a tool like Performance Monitor (perfmon) made it difficult to consume these metrics in real time.<\/p>\n

    dotnet-counters<\/code><\/h4>\n

    In 3.0-preview5, we are introducing a new command-line tool for observing metrics emitted by .NET Core Applications in real time.<\/p>\n

    You can install this .NET global tool by running the following command<\/p>\n

    dotnet<\/span> tool install --global dotnet-counters --version 1.0.3-preview5.19251.2<\/code><\/code><\/p>\n

    In the example below, we see the CPU utilization and working set memory of our application jump up when we point a load generator at our web application.<\/p>\n