For example, some garbage collection schemes are more appropriate for a given type of application. To configure WebLogic Server to detect automatically when you are running out of heap space and to address low memory conditions in the server, see Automatically Logging Low Memory Conditions and Specifying Heap Size Values.ĭepending on which JVM you are using, you can choose from several garbage collection schemes to manage your system memory. To modify heap space values, see Specifying Heap Size Values. You might see the following Java error if you are running out of heap space: To ensure maximum performance during benchmarking, you might set high heap size values to ensure that garbage collection does not occur during the entire run of the benchmark. The goal of tuning your heap size is to minimize the time that your JVM spends doing garbage collection while maximizing the number of clients that WebLogic Server can handle at a given time. If you set your heap size in accordance with your memory needs, full garbage collection is faster, but occurs more frequently. If you set a large heap size, full garbage collection is slower, but it occurs less frequently. An acceptable rate for garbage collection is application-specific and should be adjusted after analyzing the actual time and frequency of garbage collections. The JVM heap size determines how often and how long the VM spends collecting garbage. A best practice is to tune the time spent doing garbage collection to within 5% of execution time. When an object can no longer be reached from any pointer in the running program, it is considered "garbage" and ready for collection. It is a repository for live objects, dead objects, and free memory. The Java heap is where the objects of a Java program live. See "Performance Documentation For the Java Hotspot Virtual Machine: Threading" at. You can choose from multiple threading models and different methods of synchronization within the model, but this varies from JVM to JVM. Ĭhoices you make about Solaris threading models can have a large impact on the performance of your JVM on Solaris. See the support page for Mixed Client/Server JVMs at. The Supported Configurations pages at are frequently updated and contain the latest certification information on various platforms.įor WebLogic Server heap size tuning details, see Garbage Collection.Ĭhoosing a GC (garbage collection) schemeĭepending on your application, there are a number of GC schemes available for managing your system memory, as described in Choosing a Garbage Collection Scheme.ĭeployments using different JVM versions for the client and server are supported in WebLogic Server. This release of WebLogic Server supports only those JVMs that are J2SE 5.0-compliant. Use only production JVMs on which WebLogic Server has been certified. 3.Table 5-1 General JVM Tuning Considerations Tuning Factor We can spot the classic generational nature of the CMS GC in the heap configuration. As of this writing, Intellij IDEA is still using the CMS GC with the following heap info: par new generation total 613440K, used 114299KĬoncurrent mark-sweep generation total 1415616K, used 213479K Metaspace used 21031K, capacity 21241K, committed 21504K, reserved 22528KĪs shown above, we're using 28 MB of the heap and around 20 MB of metaspace. For instance, if we run the same Quarkus app with ZGC via “-XX:+UnlockExperimentalVMOptions -XX:+UseZGC”: ZHeap used 28M, capacity 200M, max capacity 1024M This output may change depending on the GC algorithm. The last line shows how much of the metaspace is used to store class information.Moreover, 13842 KB guaranteed to be available for use by the Java virtual machine, also known as committed memory Also, we can have up to 1 GB of metaspace (1048576 K). The current capacity of the metaspace is around 13.5 MB (13724 K).G1 regions are 1 MB, there are 43 regions marked as young, and 3 as survivors space.The first line reports the current heap size as 202 MB (206848 K) – also, 42 MB (43061 K) is being used.
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