我是 G1 垃圾收集的新手，但我有一个最大为 26G 的堆，初始大小为 10G，当前大小为 26G，已使用 15G。
我使用以下参数打开了 GC 日志记录:
-XX:+PrintGC -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintGCDateStamps -XX:+PrintTenuringDistribution -verbose:gc -Xloggc:
当我查看垃圾收集日志时，我注意到我的 Ref Proc 似乎花费了最长的时间。我指定了 -XX:MaxGCPauseMillis=1000 并且我的 GC 时间接近于此，但对我来说，Ref Proc 仍然运行了很长时间。我想知道是否有办法减少这个时间？
我的 GC 日志摘录:
[GC pause (young)
Desired survivor size 335544320 bytes, new threshold 15 (max 15)
- age 1: 18542272 bytes, 18542272 total
- age 2: 1752016 bytes, 20294288 total
- age 3: 1083928 bytes, 21378216 total
- age 4: 1078592 bytes, 22456808 total
- age 5: 854640 bytes, 23311448 total
- age 6: 549048 bytes, 23860496 total
- age 7: 1372744 bytes, 25233240 total
- age 8: 623048 bytes, 25856288 total
- age 9: 909984 bytes, 26766272 total
- age 10: 930072 bytes, 27696344 total
- age 11: 928088 bytes, 28624432 total
- age 12: 1053440 bytes, 29677872 total
- age 13: 553512 bytes, 30231384 total
- age 14: 787592 bytes, 31018976 total
- age 15: 985216 bytes, 32004192 total
, 1.22150400 secs]
[Parallel Time: 176.4 ms]
[GC Worker Start (ms): 209376973.5 209376973.6 209376973.6 209376973.6 209376973.7 209376973.7 209376973.7 209376973.8 209376973.8 209376973.8 209376973.8 209376973.9 209376973.9 209376974.0 209376974.0 209376974.0 209376974.0 209376974.1 209376974.1 209376974.1 209376974.1 209376974.2 209376974.2
Avg: 209376973.9, Min: 209376973.5, Max: 209376974.2, Diff: 0.7]
[Ext Root Scanning (ms): 2.2 2.0 2.2 1.5 36.8 2.2 3.6 1.6 1.6 1.6 1.7 2.2 1.7 1.5 1.5 1.5 1.5 1.8 1.7 1.6 1.3 1.6 1.7
Avg: 3.3, Min: 1.3, Max: 36.8, Diff: 35.5]
[Update RS (ms): 13.4 14.0 13.2 14.1 0.0 13.2 12.0 13.7 14.1 13.7 13.7 13.0 13.6 13.7 14.0 13.8 13.7 13.2 13.5 13.8 13.8 13.3 13.3
Avg: 13.0, Min: 0.0, Max: 14.1, Diff: 14.1]
[Processed Buffers : 8 4 16 6 0 11 10 9 14 8 8 11 15 5 7 7 13 16 9 6 12 7 13
Sum: 215, Avg: 9, Min: 0, Max: 16, Diff: 16]
[Scan RS (ms): 0.3 0.0 0.4 0.0 0.2 0.3 0.2 0.3 0.0 0.3 0.3 0.3 0.3 0.2 0.0 0.3 0.3 0.4 0.2 0.0 0.3 0.3 0.3
Avg: 0.2, Min: 0.0, Max: 0.4, Diff: 0.3]
[Object Copy (ms): 151.2 150.7 151.0 150.9 130.3 151.0 150.9 150.3 151.0 150.5 151.5 150.5 151.2 151.6 151.5 151.0 151.4 150.8 150.2 150.3 151.2 150.2 151.3
Avg: 150.0, Min: 130.3, Max: 151.6, Diff: 21.2]
[Termination (ms): 4.5 4.8 4.7 4.9 4.2 4.7 4.7 5.4 4.6 5.2 4.2 5.2 4.5 4.1 4.1 4.6 4.2 4.8 5.5 5.2 4.5 5.5 4.4
Avg: 4.7, Min: 4.1, Max: 5.5, Diff: 1.4]
[Termination Attempts : 2171 2328 2294 2328 2003 2294 2274 2497 2232 2498 1970 2481 2191 2035 2006 2287 2007 2320 2640 2554 2243 2532 2216
Sum: 52401, Avg: 2278, Min: 1970, Max: 2640, Diff: 670]
[GC Worker End (ms): 209377145.9 209377145.2 209377145.8 209377145.5 209377145.3 209377145.8 209377145.9 209377145.7 209377145.8 209377145.2 209377145.4 209377145.6 209377145.2 209377145.2 209377145.2 209377145.8 209377145.9 209377145.4 209377145.7 209377145.6 209377145.2 209377145.6 209377146.0
Avg: 209377145.6, Min: 209377145.2, Max: 209377146.0, Diff: 0.9]
[GC Worker (ms): 172.4 171.6 172.2 171.9 171.7 172.1 172.2 171.9 172.0 171.3 171.5 171.8 171.3 171.2 171.2 171.9 171.9 171.4 171.6 171.5 171.0 171.4 171.8
Avg: 171.7, Min: 171.0, Max: 172.4, Diff: 1.3]
[GC Worker Other (ms): 4.8 4.8 4.8 4.9 4.9 4.9 4.9 5.0 5.0 5.1 5.1 5.1 5.2 5.2 5.2 5.2 5.3 5.3 5.3 5.4 5.4 5.4 5.5
Avg: 5.1, Min: 4.8, Max: 5.5, Diff: 0.7]
[Clear CT: 1.9 ms]
[Other: 1043.2 ms]
[Choose CSet: 0.1 ms]
[Ref Proc: 1029.7 ms]
[Ref Enq: 5.5 ms]
[Free CSet: 6.4 ms]
[Eden: 4660M(4660M)->0B(4680M) Survivors: 460M->440M Heap: 15178M(25600M)->10501M(25600M)]
[Times: user=4.98 sys=0.00, real=1.22 secs]
最佳答案
你的意思是，除了使用更少的弱/软引用之外？
如果你想要性能，我会尽可能避免它们。您可以启用 -XX:+TraceReferenceGC 来获取有关您的引用的更多信息。
我经常建议人们尝试更大的 Eden 大小，并使用内存分析器来减少产生的垃圾量。由于从终身职位中清除了如此多的内容，您似乎获得了很多过早的晋升。
关于java - G1 垃圾收集器大部分时间都花在 Ref Proc 上，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/17853445/