negative timings in GC log

Bernd Eckenfels bernd-2014 at
Fri Feb 21 09:09:21 UTC 2014

Just a BTW: NTPd is known to not cause those problems as it does not "step" the clock, this does more happen if you use ntpdate in cron or the VMTools. I would advice against both in Java systems.

However I wonder if - similar to other timed primitives - it is time to reconsider switching of the clock source for those timings?

> Am 21.02.2014 um 09:27 schrieb Kirk Pepperdine <kirk at>:
> Hi all,
> More of an FYI but I sometimes run across things that look like this.
> [PSYoungGen: 2096928K->64K(2097024K)] 3981201K->1884337K(4194176K), -0.2652920 secs] [Times: user=0.04 sys=0.00, real=0.02 secs]
> This is coming from a 1.7.0 JVM but I fear I won’t be able to determine the exact build. The JVM was running in a virtualized environment. My guess is something like this could happen if something (NTP?) has diddled with the clock. My question is, would it be better to leave it as is or report it as 0 or unknown?
> Regards,
> Kirk

More information about the hotspot-gc-dev mailing list