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garbage-collectionjvmjvm-hotspot
terry
terry

Reputation: 123

what is sequential store buffer structure in gc specifically?

I have read garbage collection book, it mentioned a sort of data structure ,sequential store buffer , could anyone help me to explain how it works? or the principle? or where i can find the thesis about it ?

Upvotes: 0

Views: 167

Answers (1)

Speakjava
Speakjava

Reputation: 3400

For generational collectors, different regions of the heap get collected at different times (minor for young gen., major for old gen.). To ensure consistency of collection a remembered set is typically used that records links from objects in the old generation to the young generation.

There are different ways of recording the remembered set, as described in the GC book you mention. A common way is the use of a card table, which is how the G1 collector does it.

An alternative is the sequential store buffer. This is an area of memory that is treated roughly like a stack, i.e. there is a pointer to where the next piece of data can be stored. Once the data is saved the pointer is bumped by the size of the data. This is very efficient (and is also the way space is allocated in the young generation). For a GC algorithm that uses a write-barrier (most) this is a good way of reducing the load created by the write-barrier. It is also very efficient on pipelined architectures with branch prediction.

Upvotes: 2

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