我想知道Java進程在某個特定時間使用的總堆大小,我必須使用jmap。用jmap查找當前堆大小
的jmap -heap <pid>
輸出給了我這樣的事情:
Attaching to process ID 2899, please wait... Debugger attached successfully. Server compiler detected. JVM version is 14.2-b01 using thread-local object allocation. Parallel GC with 2 thread(s) Heap Configuration: MinHeapFreeRatio = 40 MaxHeapFreeRatio = 70 MaxHeapSize = 1258291200 (1200.0MB) NewSize = 1048576 (1.0MB) MaxNewSize = 4294901760 (4095.9375MB) OldSize = 4194304 (4.0MB) NewRatio = 8 SurvivorRatio = 8 PermSize = 16777216 (16.0MB) MaxPermSize = 67108864 (64.0MB) Heap Usage: PS Young Generation Eden Space: capacity = 119013376 (113.5MB) used = 117277608 (111.84464263916016MB) free = 1735768 (1.6553573608398438MB) 98.54153536489882% used From Space: capacity = 131072 (0.125MB) used = 81920 (0.078125MB) free = 49152 (0.046875MB) 62.5% used To Space: capacity = 131072 (0.125MB) used = 0 (0.0MB) free = 131072 (0.125MB) 0.0% used PS Old Generation capacity = 954466304 (910.25MB) used = 80791792 (77.04905700683594MB) free = 873674512 (833.2009429931641MB) 8.46460390077846% used PS Perm Generation capacity = 57671680 (55.0MB) used = 41699008 (39.76727294921875MB) free = 15972672 (15.23272705078125MB) 72.30413263494319% used
我可以使用這些值的公式,找出所使用的總內存?
有關我如何在Linux上發現這個問題的其他建議,歡迎使用jmap,但是我們會優先考慮jmap。
感謝
運行'jmap -heap:format = b'並使用Eclipse中的內存分析工具解析堆轉儲文件使我總共22MB。我無法找到一種方法來獲得相同的總價值... –
fmoga
2010-02-24 08:48:59
@MelmanRo:我的猜測是,eclipse工具從計算中刪除了所有不可達(即待收集的垃圾)對象,這是計算如果完整的GC掃描運行,堆大小將會是多少。正如我所描述的,我認爲當前*實際*操作系統的內存使用量是各個池的總和。 – skaffman 2010-02-24 08:52:37
這可以成爲如此巨大差異的根源嗎? – fmoga 2010-02-24 09:56:36