Strange STW pauses

[Kirk Pepperdine]

Hi Nick,

I think it would be worth posting the GC log as long as it was collected with the option that I recommended. Even if this isn’t GC related, there is likely some information in the log that might yield a clue.

Kind regards,
Kirk Pepperdine

> On Aug 23, 2017, at 10:48 AM, Nick Chadwick <nick.chadwick at nichesolutions.co.uk> wrote:
> 
> Thanks both for your replies.
> 
> Yes, it is a recurring issue - it doesn't go away after the JVM has warmed
> up. I am able to trigger the pauses quite easily and regularly with minimal
> load.
> 
> I am already logging GC in addition, but there are no GCs close to the
> pauses that I am seeing. As I understand it, the log entries above are
> explicitly not garbage collections - they would show something other than
> "no vm operation" under vmop (e.g. CollectForMetadataAllocation,
> ParallelGCFailedAllocation, etc) - but guaranteed safepoints. I understand I
> can tweak the GuaranteedSafepointInterval, but that doesn't feel like the
> solution to me, and would probably just make the pauses longer, albeit less
> often.
> 
> If you do think it's still worth me posting some GC logs here as well, I
> can, but it definitely feels like it is not GC-related. (I am running with a
> large heap, and see only a few, short pauses for GC)
> 
> Although I agree it looks like the vmop itself is not taking up the time, I
> am seeing stop-the-world pauses that correlate very closely with the total
> time spent under sync/cleanup in these specific pauses.
> 
> Grateful for any further insight.
> 
> 
> 
> --
> View this message in context: http://openjdk.5641.n7.nabble.com/Strange-STW-pauses-tp312324p312352.html
> Sent from the OpenJDK Hotspot Runtime System mailing list archive at Nabble.com.