Long young generation GC?

Y. Srinivas Ramakrishna y.s.ramakrishna at oracle.com
Mon Oct 25 17:49:33 PDT 2010


On 10/25/2010 5:32 PM, Hi Guava wrote:
> The third young generation GC took 439.2720750 secs but the user and
> real time are only 0.08 seconds. What does it mean?

The machine may be using NTP, and the time may have been changed?
JVM timestamps on Linux seem still to be based on TOD rather than
on TSC. Someone in the runtime team (cc'd) may have more detail on
why that might still be so.

-- ramki


>
> 72667.213: [GC 72667.213: [ParNew: 38336K->4224K(38336K), 1.2473840 secs]
> 3443948K->3420569K(6549376K), 1.2474290 secs] [Times: user=0.64 sys=1.10,
> real=1.25 secs]
> 72680.531: [GC 72680.532: [ParNew: 38336K->4221K(38336K), 0.2916570 secs]
> 3008948K->2979033K(6549376K), 0.2916710 secs] [Times: user=0.26 sys=0.03,
> real=0.29 secs]
> 72681.425: [GC 72681.426: [ParNew: 38325K->4224K(38336K), 439.2720750
> secs] 3013053K->2979055K(6549376K), 439.2720750 secs] [Times: user=0.08
> sys=0.00, real=0.08 secs]
>
> Environment:
> Java HotSpot(TM) 64-Bit Server VM Version 1.6.0_20-b02
> Linux Version 2.6.18-128.1.1.el5 on amd64
> -Xms6400m
> -Xmx6400m
> -Xss256k
> -XX:+UseConcMarkSweepGC
> -XX:+PrintGCDetails
> -XX:+PrintGCTimeStamps
> -XX:+UseCompressedOops
> _______________________________________________
> hotspot-gc-use mailing list
> hotspot-gc-use at openjdk.java.net
> http://mail.openjdk.java.net/mailman/listinfo/hotspot-gc-use

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