EF6 Performance Issues

What are the issues?The most common issue being encountered is a significantly slower startup time when running with the debugger attached. Here is a complete list of the performance related issues we are tracking.


When will a fix be available?

We are working to put together a 6.0.2 patch release that addresses the performance issues and some other high priority bugs. We are working to make this patch available quickly, but we also want to make sure we capture as many issues as possible and perform adequate testing to ensure we don’t introduce new issues. While we don’t have definite plans for a release date yet, we’re aiming to make it available in November.

You can view the issues being tracked for inclusion in this patch on our CodePlex site. Note that some issues are still being investigated and won’t show up in the 6.0.2 release until we have identified the root cause.


Why did you miss this stuff?

Unfortunately it is not practical  – or even possible – to cover every scenario in our suite of performance tests. Some of these issues have exposed holes in our test suite that we are working to fill. Other issues only manifest when certain model sizes/shapes/patterns are present and they just happen to be areas that are not covered by our test suite.

We realize that reliable performance is important to you, your business, and your customers and we don’t take this situation lightly. In addition to rounding out our performance test suite we will also be reviewing the issues identified in EF6 to understand how we can avoid such issues in the future.


The already released 6.0.1 patch release

The 6.0.0 version of the EF package needed to be locked down early to be included in Visual Studio, ASP.NET, etc. After this lock down we identified some other performance issues that we felt needed to be addressed ASAP.

At the same time we released 6.0.0 we also published a 6.0.1 patch release that addressed these issues. If you install from NuGet you will automatically get the latest patch version. If you use a VS2013 project template that already has EF6 installed, or if the EF6 tooling installs the NuGet package for you, we would recommend updating to the latest patch version. You can do this by running Update-Package EntityFramework in Package Manager Console.

You can see a complete list of the individual fixes in this patch on our CodePlex site.


Improving startup performance with Ngen

Prior to EF6, a large portion of Entity Framework was included in the .NET Framework. This meant that most of Entity Framework automatically has native image generation run on it to reduce the just-in-time (JIT) compilation cost.

Because EF6 ships as a completely out-of-band release, native image generation is no longer performed automatically. This can result in an increased warm-up time for your application while JIT compilation occurs – we have seen results of around 1 second.

To remove this JIT time you can use Ngen to generate native images for the Entity Framework assembly on your machine. For more information, see Improving Startup Performance with NGen.