jprofiler find garbage collector algorithm

When the Survivor space is not enough, we need to rely on other memory (here refers to the old age). We have no way to ensure that no more than 10% of the objects survive each recycling.

Of course, 98% of the objects that can be recycled are only data in general scenarios. When recycling, copy the surviving objects on Eden and Survivor to another Survivor at one time, and finally clear the space of Eden and Survivor. Use Eden and one of the Survivor pieces each time. Instead, the memory is divided into a larger Eden space and two smaller Survivor spaces. Special research by IBM shows that 98% of the objects in the new generation are 'dead', so there is no need to divide the memory space according to the ratio of 1:1. Improved optimization : Today's commercial virtual machines use this collection algorithm to recycle the young generation. ②Simple implementation and efficient operation.ĭisadvantages: Only general memory can be used, and the memory sacrifice is too large.

The memory space is cleared at one time.Īdvantages: ① No need to consider complex situations such as memory fragmentation. When this block of memory is used up, the surviving objects are copied to the other block, and then the used objects are copied. It divides the available memory into two equal-sized blocks according to the capacity, and only uses one of them at a time. To address the efficiency issue, a collection algorithm called 'replication' emerged. Too much fragmented space may cause that when a large object needs to be allocated during the running process of the program, it cannot find enough continuous memory and has to trigger the garbage collection action in advance. ②Space problem : After the mark is cleared, a large number of discontinuous memory fragments will be generated. Just like his name, the algorithm is divided into two stages: 'marking' and 'clearing': first, all objects that need to be recycled are marked, and all marked objects are uniformly recycled after the marking is completed.ĭisadvantages: ① Efficiency problem : The efficiency of both marking and clearing processes is not very high.

Jprofiler find garbage collector algorithm