Advanced configuration

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 CLion. 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.

For more information, refer to Increase the memory heap of the IDE.

-Xms

Specifies the initial memory allocated by the JVM for running CLion. 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.

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 CLion 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 CLion 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 CLion 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

CLion 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.