dotnet enables JIT multi-core compilation to improve startup performance

It takes 2 minutes to improve the startup performance by one-tenth, and the startup performance can be improved by starting JIT multi-core compilation in the desktop program. In dotnet, the startup performance of the software can be improved by allowing JIT to perform multi-core compilation. In the default managed ASP.NETThe program is enabled, and it needs to be manually opened for desktop programs such as WPF.

Add the following code to the Main function or App's constructor to open

using System.Runtime;ProfileOptimization.SetProfileRoot(@"C:\lindexi\");ProfileOptimization.StartProfile("Startup.Profile");

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Set a folder in SetProfileRoot. This folder needs to be an existing folder. If it is set to a folder that does not exist, then this method will not be abnormal, but will not do anything

Set a file name in StartProfile, which will record the function that needs to be called when the file is started

Principle

On devices that can perform multi-threaded computing, one thread can run the code, and multiple threads can perform JIT compilation to improve performance.

Set a folder in SetProfileRoot, which will store files used to improve performance, in StartProfile will create a binary file to record the functions that need to be called at startup

When the program is run for the first time, it will judge whether there are files to improve performance. If not, collect the functions that need to be called in the background at startup, and record these functions in the files to improve performance.

When the program is run for the second time, because there is already a performance-improving file, reading this file can know the functions that need to be called at startup, so the background multi-threaded JIT compilation is performed to these methods that will be called

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Enable this function

By default, this function is enabled in ASP.NET. If you need to disable this function, please add the following code to the web.config file

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Desktop programs such as WPF are not enabled by default. You need to call the two functions mentioned at the beginning of this article to enable them. It should be noted that the order of the two methods is fixed. First set the folder and then set the file. Note that the set folder needs to beThe file exists and can be written to at the same time

Please call SetProfileRoot two functions during program execution, such as Main or App constructor

If an application has different running methods according to the incoming command line, such as the software I am working on, there are two different methods: lesson preparation and teaching. These two different methods start the method that needs to be called.If they are not the same, you need to use two different files in StartProfile through the command line, and use different files for different modes

ProfileOptimization.SetProfileRoot(@"C:\lindexi\");if (Editing){// Now enter lesson preparation modeProfileOptimization.StartProfile("Editing.Profile");}else{// now using the teaching methodProfileOptimization.StartProfile("Displaying.Profile");}

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Here you can use different files according to different command parameters, so that different commands can do different optimizations for different startup methods used

Environment

Required on a non-single-core device, and on .NET Framework 4.5 and above or dotnet core 3.0 and above

Performance

After many tests, I found that the time required to call the two functions of SetProfileRoot is about 0.2 ms on my device, which is not too short. At the same time, I found that the actual time to the completion of the software startup has hardly improved

Because the startup time of many software is in file reading and writing, not in JIT compilation time

So there is almost no improvement in startup performance without this function and startup

Why isn't this feature turned on in the default desktop program?Because this function needs to read and write files that improve performance, it is difficult to know where the file should be placed by default, and the time to read the file at startup is often longer than JIT compilation.

In ASP.NET, you can automatically read files that improve performance by hosting, so it is used in ASP.NET by default

You can also use ladder compilation at software startupThe methods used in the process use fast compilation methods to reduce the time of JIT execution