Advanced configuration

Besides the standard options available in the IDE settings, MPS enables you to perform low-level configuration of the underlying platform and the Java runtime.

JVM options

MPS runs on the Java Virtual Machine (JVM), which has various options that control its performance.

The default options used to run MPS are specified in the IDE installation directory:

<IDE_HOME>\bin\mps64.exe.vmoptions

MPS.app/Contents/bin/mps.vmoptions

<IDE_HOME>/bin/mps64.vmoptions

Configure JVM options

Do one of the following to create a copy of the default file with JVM options in the configuration directory that will override the original file:

In the main menu, go to Help | Edit Custom VM Options.
If you do not have any project open, on the Welcome screen, click Configure and then Edit Custom VM Options.
If you cannot start MPS, manually copy the default file with JVM options to the MPS configuration directory.

If you do not have write access to the MPS configuration directory, you can add the MPS_VM_OPTIONS environment variable to specify the location of the file with your preferred JVM options. This file will override both the original default file and the copy located in the MPS configuration directory.

Locate the JVM options file

If you are not sure where MPS is getting its JVM options, check the following:

The location specified by the MPS_VM_OPTIONS environment variable. If the specified file exists, it will override all other JVM options files.
If the Toolbox App manages your current MPS instance, open the Toolbox App, click next to the relevant IDE instance, and select Settings. Under Configuration, find Java Virtual Machine options and click Edit.
If you are running a standalone MPS instance, check the configuration directory.
If there are no JVM options files defined in the previous locations, MPS will use the default JVM options file. Do not modify it. Use it only to check what are the default options that MPS uses.

Common options

The default values of the JVM options should be optimal in most cases. The following are the most commonly modified ones:

-Xmx

Limits the maximum memory heap size that the JVM can allocate for running MPS. The default value depends on the platform. If you are experiencing slowdowns, you may want to increase this value, for example, to set the value to 2048 megabytes, change this option to -Xmx2048m.

-Xms

Specifies the initial memory allocated by the JVM for running MPS. The default value depends on the platform. It is usually set to about half of the maximum allowed memory (see -Xmx), for example, -Xms1024m.

-XX:NewRatio

Specifies the ratio between the size of the young and old generation in the heap. In most cases, a ratio between 2 and 4 is recommended. This will set the size of the young generation to be 1/2 to 1/4 of the old generation correspondingly, which is good when you are often working on one project and only a few files at a time. However, if you are constantly opening new files and switching between several projects, you may need to increase the young generation. In this case, try setting -XX:NewRatio=1, which will make the young generation as large as the old generation, allowing objects to remain in the young generation for longer.

For more information, see Java Garbage Collection Basics.

Specify each option on a separate line. Example JVM options file:

                -Xmx4G
                -Xms2G
                -XX:NewRatio=4
            

For more information about the available JVM options, refer to the java command reference.

Platform properties

MPS enables you to customize various platform-specific properties, such as the path to user-installed plugins and the maximum supported file size. The default properties used to run MPS are specified in the IDE installation directory:

<IDE_HOME>\bin\idea.properties

MPS.app/Contents/bin/idea.properties

<IDE_HOME>/bin/idea.properties

Configure platform properties:

Do one of the following to create an empty idea.properties file in the configuration directory that will override the values from the original file:

Go to Help | Edit Custom Properties.
If you do not have any project open, on the Welcome screen, click Configure and then select Edit Custom Properties.
If you cannot start MPS, manually create an empty idea.properties file in the MPS configuration directory.

If you do not have write access to the MPS configuration directory, you can add the MPS_PROPERTIES environment variable to specify the location of the idea.properties file. The properties in this file will override the corresponding properties in both the original default file and the one located in the MPS configuration directory.

Common properties

Users often change the location of the default IDE directories. For more information, refer to Change the location of IDE directories.

Limits that can affect performance:

idea.max.content.load.filesize: Maximum size of files (in kilobytes) that MPS is able to open. Working with large files can affect editor performance and increase memory consumption. The default value is 20000.
idea.max.intellisense.filesize: Maximum size of files (in kilobytes) for which MPS provides coding assistance. Coding assistance for large files can affect editor performance and increase memory consumption. The default value is 2500.
idea.cycle.buffer: Maximum size of the console cyclic buffer (in kilobytes). If the console output size exceeds this value, the oldest lines are deleted. To disable the cyclic buffer, set idea.cycle.buffer.size=disabled.
idea.max.vcs.loaded.size.kb: Maximum size (in kilobytes) that MPS loads for showing past file contents when comparing changes. The default value is 20480.

Specify each property on a separate line. Example platform properties file:

                idea.max.intellisense.filesize=5000
                idea.cycle.buffer.size=1024
            

MPS provides a number of other properties that define interaction with the environment (window managers, launchers, the file system, and so on). Most of them act like hidden settings (in the sense that they are not evidently exposed), which you may need to enable or disable in certain cases. Change these properties only if advised by JetBrains Support.

Last modified: 26 May 2024