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http://www.javaperformancetuning.com/news/newtips072.shtml

With a large heap memory, the garbage collection (GC) operation could become a major performance bottleneck. It could take more than ten seconds for the GC to sweep through a multiple gigabyte heap.
If your priority is to increase the total throughput of the application and you can tolerate occasional GC pauses, you should use the -XX:UseParallelGC and -XX:UseParallelOldGC
If you need to minimize the GC pause, you can use the -XX:+UseConcMarkSweepGC flag to turn on the concurrent GC, but this does reduce the overall GC throughput.

停止時間とスループット(単位時間あたりの処理能力)のトレードオフ

-XX:+UseParallelOldGC スループット
-XX:+UseConcMarkSweepGC 停止時間

ってこと？