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This article mainly introduces what are the common GC parameters in Java. It is very detailed and has certain reference value. Friends who are interested must finish it!

1. Parameters related to serial collectors

-XX:+ UseSerialGC: using serial collectors in the new and old generations

-XX:SurvivorRatio: sets the ratio of the eden zone size to the survivior zone size.

-XX:PretenureSizeThreshold: sets the threshold for large objects to enter the old age directly. When the size of the object exceeds this value, it will be directly in the old age

-XX:MaxTenuringThreshold: sets the maximum age at which the object enters the old age. After each MinorGC, the age of the object is increased by 1. Anyone older than this age is bound to enter the old age.

two。 Parameters related to parallel collectors

-XX:+UseParNewGC: use parallel collectors in the new generation.

-XX:+UseParallelOldGC: parallel recycling collectors were used in the old days.

-XX:ParallelGCThreads: sets the number of threads used for garbage collection. In the case of passing, it can be equal to the number of CPU, but in the case of a large number of CPU, it is reasonable to set a relatively small value.

-XX:MaxGCPauseMillis: sets the maximum garbage collection pause time. Its value is an integer greater than 0. As the collector works, it adjusts the Java heap size or other parameters to keep the pause time within MaxGCPauseMillis as much as possible.

-XX:GCTimeRatio: sets the throughput size. Its value is an integer between 0 and 100. Assuming that the value of GCTimeRatio is n, the system will spend no more than 1 / (1 + n) of the time on garbage collection.

-XX:+UseAdaptiveSizePolicy: open the adaptive GC policy. In this mode, parameters such as the size of the new generation, the ratio of eden to survivior, and the age of the object in the old age are automatically adjusted to achieve a balance between heap size, throughput and pause time.

3. Parameters related to the CMS collector

-XX:+UseConcMarkSweepGC: parallel collectors are used in the new generation and CMS+ serial collectors are used in the old days.

-XX:ParallelCMSThreads: sets the number of threads for CMS.

-XX:CMSInitiatingOccupancyFraction: sets the CMS collector to be triggered after how much space is used in the old era. Default is 68%.

-XX:+UseCMSCompactAtFullCollection: sets whether the CMS collector will defragment the memory after completing garbage collection.

-XX:CMSFullGCsBeforeCompaction: sets the number of CMS garbage collection times, followed by a memory compression.

-XX:+CMSClassUnloadingEnabled: allows the collection of class metadata areas.

-XX:CMSInitiatingPermOccupancyFraction: when the permanent zone occupancy reaches this percentage, CMS recycling is started (provided-XX:+CMSClassUnloadingEnabled is activated).

-XX:UseCMSInitiatingOccupancyOnly: indicates that CMS recycling occurs only when the threshold is reached.

-XX:+CMSIncrementalMode: use incremental mode, which is more suitable for single CPU. Incremental mode is marked as obsolete in JDK8 and will be removed completely in JDK9.

4. Parameters related to the G1 recycler

-XX:+UseG1GC: use the G1 recycler.

-XX:MaxGCPauseMillis: sets the maximum garbage collection pause time.

-XX:GCPauseIntervalMillis: sets the pause interval.

5. TLAB correlation

-XX:+UseTLAB: enable TLAB allocation.

-XX:+PrintTLAB: print TLAB related assignments

-XX:TLABSize: sets the TLAB size.

-XX:+ResizeTLAB: automatically resize TLAB.

6. Other parameters

-XX:+DisableExplicitGC: disable explicit GC

-XX:+ExplicitGCInvokesConcurrent: use concurrency to handle explicit GC

These are all the contents of the article "what are the common GC parameters in Java?" Thank you for reading! Hope to share the content to help you, more related knowledge, welcome to follow the industry information channel!

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