UseConcMarkSweepGC vs UseParallelGC

Question

我目前遇到很长时间的垃圾收集问题.请参阅以下内容.我目前的设置是我使用-Xms1g和-Xmx3g.我的应用程序使用的是java 1.4.2.我没有设置任何垃圾收集标志.从它的外观来看,3gb是不够的,我真的有很多垃圾收集对象.

题:

我应该改变我的垃圾收集算法吗？我应该用什么？是否更好用-XX:+UseParallelGC or -XX:+UseConcMarkSweepGC

或者我应该使用这种组合

-XX:+UseParNewGC -XX:+UseConcMarkSweepGC

占用内存的主要是报告数据而不是缓存数据.此外,该机器有16GB的内存,我打算将堆增加到8GB.

这两个选项有什么区别,因为我仍然觉得很难理解.该机器有多个处理器.我可以接受长达5秒的点击,但30到70秒真的很难.

谢谢您的帮助.

  Line 151493: [14/Jan/2012:11:47:48] WARNING ( 8710): CORE3283: stderr: [GC 1632936K->1020739K(2050552K), 1.2462436 secs]
    Line 157710: [14/Jan/2012:11:53:38] WARNING ( 8710): CORE3283: stderr: [GC 1670531K->1058755K(2050552K), 1.1555375 secs]
    Line 163840: [14/Jan/2012:12:00:42] WARNING ( 8710): CORE3283: stderr: [GC 1708547K->1097282K(2050552K), 1.1503118 secs]
    Line 169811: [14/Jan/2012:12:08:02] WARNING ( 8710): CORE3283: stderr: [GC 1747074K->1133764K(2050552K), 1.1017273 secs]
    Line 175879: [14/Jan/2012:12:14:18] WARNING ( 8710): CORE3283: stderr: [GC 1783556K->1173103K(2050552K), 1.2060946 secs]
    Line 176606: [14/Jan/2012:12:15:42] WARNING ( 8710): CORE3283: stderr: [Full GC 1265571K->1124875K(2050552K), 25.0670316 secs]
    Line 184755: [14/Jan/2012:12:25:53] WARNING ( 8710): CORE3283: stderr: [GC 2007435K->1176457K(2784880K), 1.2483770 secs]
    Line 193087: [14/Jan/2012:12:37:09] WARNING ( 8710): CORE3283: stderr: [GC 2059017K->1224285K(2784880K), 1.4739291 secs]
    Line 201377: [14/Jan/2012:12:51:08] WARNING ( 8710): CORE3283: stderr: [Full GC 2106845K->1215242K(2784880K), 30.4016208 secs]


xaa:1: [11/Oct/2011:16:00:28] WARNING (17125): CORE3283: stderr: [Full GC 3114936K->2985477K(3114944K), 53.0468651 secs] --> garbage collection occurring too often as noticed in the time. garbage being collected is quite low and if you would notice is quite close the the heap size. during the 53 seconds, this is equivalent to a pause.
xaa:2087: [11/Oct/2011:16:01:35] WARNING (17125): CORE3283: stderr: [Full GC 3114943K->2991338K(3114944K), 58.3776291 secs]
xaa:3897: [11/Oct/2011:16:02:33] WARNING (17125): CORE3283: stderr: [Full GC 3114940K->2997077K(3114944K), 55.3197974 secs]
xaa:5597: [11/Oct/2011:16:03:00] WARNING (17125): CORE3283: stderr: [Full GC[Unloading class sun.reflect.GeneratedConstructorAccessor119]
xaa:7936: [11/Oct/2011:16:04:36] WARNING (17125): CORE3283: stderr: [Full GC 3114938K->3004947K(3114944K), 55.5269911 secs]
xaa:9070: [11/Oct/2011:16:05:53] WARNING (17125): CORE3283: stderr: [Full GC 3114937K->3012793K(3114944K), 70.6993328 secs]

Answer 1

由于您有极长的GC暂停,因此不认为更改GC算法会有所帮助.

请注意,您只有完整的集合是非常可疑的.也许你需要增加年轻一代和/或幸存者空间的规模.

也可以看看:

• 使用1.4.2 Java [tm]虚拟机调整垃圾收集