-xx:+useserialgc |
The JVM runs the default value in client mode, and after this switch is turned on, memory recycling is performed using the collector combination of Serial + Serial old |
-xx:+useparnewgc |
After you turn on this switch, use Parnew + Serial old collector for garbage collection |
-xx:+useconcmarksweepgc |
Using parnew + cms + Serial old collector combination for memory reclamation, Serial old as the CMS "Concurrent Mode Failure" After the failure of the fallback collector. |
-xx:+useparallelgc |
The JVM runs the default value in Server mode, and when this switch is turned on, it is recycled using the collector combination of parallel scavenge + Serial old |
-xx:+useparalleloldgc |
Recycling with collector combinations of Parallel scavenge + Parallel old |
-xx:survivorratio |
The capacity ratio of the Eden region to the survivor region in the Cenozoic, the default is 8, which represents eden:subrvivor = 8:1 |
-xx:pretenuresizethreshold |
Directly promoted to the size of the old age object, after setting this parameter, objects larger than this parameter will be allocated directly in the old age |
-xx:maxtenuringthreshold |
Promotion to the age of the old, each time after minor GC, the age of 1, when the value of this parameter to enter the old age |
-xx:useadaptivesizepolicy |
Dynamically adjusts the size of each area in the Java heap and the age of entry into the old age |
-xx:+handlepromotionfailure |
Whether to allow the new generation to collect the guarantee, once minor GC, another piece of survivor space is not enough, will be directly in the old age to retain |
-xx:parallelgcthreads |
Set the number of threads in a parallel GC for memory reclamation |
-xx:gctimeratio |
GC time is the column of the total time, the default value is 99, which is to allow 1% GC time, only valid when using the parallel scavenge collector |
-xx:maxgcpausemillis |
Set maximum pause time for GC, valid under parallel scavenge collector |
-xx:cmsinitiatingoccupancyfraction |
Set the CMS collector to start garbage collection after the old age space is used, the default value is 68%, only valid in the CMS collector,-xx:cmsinitiatingoccupancyfraction=70 |
-xx:+usecmscompactatfullcollection |
Because the CMS collector is fragmented, this parameter sets whether a memory defragmentation process is required after the garbage collector, only valid when the CMS collector |
-xx:+cmsfullgcbeforecompaction |
Set up a CMS collector to perform a memory defragmentation process after several garbage collections, usually with the usecmscompactatfullcollection parameter |
-xx:+usefastaccessormethods |
Original type optimization |
-xx:+disableexplicitgc |
Whether to turn off manual System.GC |
-xx:+cmsparallelremarkenabled |
Reduce Mark pauses |
-xx:largepagesizeinbytes |
The size of the memory page cannot be set too large, affecting the size of the perm,-xx:largepagesizeinbytes=128m |