Serial Collector Stops Application for Minor/Major GC

Java GC Tutorials - Herong's Tutorial Examples

∟Serial Collector Stops Application for Minor/Major GC

This section provides log messages showing that the Serial Collector stops the application for both Minor GC and Major GC.

One impact of using the Serial Collector is that it performs both Minor and Major collection in a stop-the-world fashion (application pause). But there seems to be no easy way to do this in JVM 9 or higher releases. I could not find any "-Xlog" options to generate any log messages about when and for how long application gets stopped by the Serial Collector.

However if you are still using JVM 8 or older releases, you can confirm stop-the-world behavior of the Serial Collector with "-XX:+PrintGCApplicationStoppedTime" and "-XX:+PrintGCApplicationConcurrentTime" JVM options:

herong> \Progra~1\java\jdk1.8.0\bin\java -Xms2m -Xmx64m -XX:+PrintGC
   -XX:+PrintGCApplicationStoppedTime -XX:+PrintGCApplicationConcurrentTime
   -XX:+PrintGCTimeStamps -XX:+UseSerialGC GarbageCollection

Step/TotalMemory/FreeMemory/UsedMemory:
0.114: Application time: 0.0088216 seconds
   -- Application executed for 0.0088216 seconds with no stop

0.115: [GC (Allocation Failure)  878K->755K(1984K), 0.0017072 secs]
   -- Serial Collector did a Minor GC

0.117: Total time for which application threads were stopped: 0.0025561 s,
   Stopping threads took: 0.0000456 seconds
   -- Serial Collector did stop the application for 0.0025561 seconds

1   2031616   698704   1332912
1.109: Application time: 0.9924986 seconds
   -- Application executed for 0.9924986 seconds with no stop

1.110: [GC (Allocation Failure)  1557K->1540K(2500K), 0.0054299 secs]
1.117: [Full GC (Allocation Failure)  1540K->1540K(2500K), 0.0052930 secs]
   -- Serial Collector did a Major (labeled as Full) GC

1.123: Total time for which application threads were stopped: 0.0135217 s,
   Stopping threads took: 0.0000990 seconds
   -- Serial Collector did stop the application for 0.0135217 seconds

2   3874816   1473136   2401680
2.128: Application time: 1.0044262 seconds
   -- Application executed for 1.0044262 seconds with no stop

2.130: [GC (Allocation Failure)  2601K->2580K(3784K), 0.0047073 secs]
   -- Serial Collector did a Minor GC

2.135: Total time for which application threads were stopped: 0.0064456 s,
   Stopping threads took: 0.0001472 seconds
   -- Serial Collector did stop the application for 0.0064456 seconds

3   3874816   425272   3449544
3.131: Application time: 0.9955077 seconds
   -- Application executed for 1.9955077 seconds with no stop

3.133: [GC (Allocation Failure)  3624K->3620K(4820K), 0.0055259 secs]
3.139: [Full GC (Allocation Failure)  3620K->3620K(4820K), 0.0057639 secs]
   -- Serial Collector did a Major (labeled as Full) GC

3.146: Total time for which application threads were stopped: 0.0136471 s,
   Stopping threads took: 0.0001502 seconds
   -- Serial Collector did stop the application for 0.0136471 seconds
...

The GC log messages confirm that:

Serial Collector stops the application to perform Minor GC.
Serial Collector stops the application to perform Major GC.
Serial Collector stops the application for a longer period of time for Major GC than Minor GC.