若い世代、テニュア世代、パーマ世代に空き容量があるにもかかわらず、4000 秒ごとにフル GC が発生するのはなぜですか。
GC パラメータ:
-XX:CMSInitiatingOccupancyFraction=50
-XX:+UseCMSInitiatingOccupancyOnly
-XX:+UseConcMarkSweepGC
-XX:+UseParNewGC
-Xloggc:GC.log
-XX:+PrintGCDetails
-XX:+PrintTenuringDistribution
-XX:MaxTenuringThreshold=8
-XX:PermSize=128M
-XX:MaxPermSize=128M
-XX:+CMSPermGenSweepingEnabled
jvm 引数:
-Xms25G -Xmx25G
gc ログは次のとおりです。
22463.534: [GC 22463.534: [ParNew
Desired survivor size 8716288 bytes, new threshold 3 (max 8)
- age 1: 3725848 bytes, 3725848 total
- age 2: 3199384 bytes, 6925232 total
- age 3: 2962800 bytes, 9888032 total
: 150702K->15367K(153344K), 0.0343470 secs] 5647083K->5515157K(26197376K), 0.0344540 secs] [Times: user=0.21 sys=0.00, real=0.04 secs]
22476.236: [GC 22476.236: [ParNew
Desired survivor size 8716288 bytes, new threshold 3 (max 8)
- age 1: 4130920 bytes, 4130920 total
- age 2: 3110336 bytes, 7241256 total
- age 3: 3125208 bytes, 10366464 total
: 151687K->16210K(153344K), 0.0357830 secs] 5651477K->5519299K(26197376K), 0.0358820 secs] [Times: user=0.22 sys=0.00, real=0.04 secs]
**22478.730: [Full GC (System) 22478.730: [CMS: 5503089K->4624468K(26044032K), 33.8259070 secs] 5560326K->4624468K(26197376K), [CMS Perm : 12045K->11957K(131072K)], 33.8260340 secs] [Times: user=33.38 sys=0.06, real=33.83 secs]**
22513.164: [GC 22513.164: [ParNew
Desired survivor size 8716288 bytes, new threshold 8 (max 8)
- age 1: 4477888 bytes, 4477888 total
: 136320K->9674K(153344K), 0.0734160 secs] 4760788K->4634143K(26197376K), 0.0735590 secs] [Times: user=0.55 sys=0.00, real=0.08 secs]
22522.765: [GC 22522.766: [ParNew
Desired survivor size 8716288 bytes, new threshold 8 (max 8)
- age 1: 3725528 bytes, 3725528 total
- age 2: 4220800 bytes, 7946328 total
: 145994K->8939K(153344K), 0.0226740 secs] 4770463K->4633407K(26197376K), 0.0228130 secs] [Times: user=0.15 sys=0.00, real=0.03 secs]