YGC time increasing suddenly

[Luciano Molinari]

Hello everybody,

*Bernd*,

Yes, yesterday I found out that my system is NUMA:
# numactl --hardware
available: 2 nodes (0-1)
node 0 size: 8056 MB
node 0 free: 4312 MB
node 1 size: 8080 MB
node 1 free: 1543 MB
node distances:
node   0   1
  0:  10  20
  1:  20  10

Until today I wasn't using huge pages, but today I ran a test locking my
app in only one NUMA node (Wolfgang's tip) and using
huge pages. As the app has less resources in this case, I decreased the
request rate to 7k/s. The app ran properly for
about ~35min and then the same problem appeared.

What's the best way to setup
the JVM considering NUMA?Disable NUMA?Run JVM with -XX:+UseNUMA?I'll run a
test with this parameter.

I collected the number the number of threads created since VM start:
1451. However, the number of live threads was kept at about 300 threads.

*Jon*,
I ran a test using -XX:+PrintReferenceGC parameter and there's a link to
the GC output in the end of this e-mail. I couldn't find anything too
weird..maybe I didn't analyze it properly.

*Srinivas*,
Yes, as soon as I start to see longer pauses the promotion rate rapidly
increases.

As it was pointed out in one of the previous e-mail and I checked today
using JConsole, survivor space is almost empty while YGC time is OK, with
just a few MB in use. But when YGC time increase, survivor also starts to
become full, which must explain the increasing promotion rate.

Both young gc and promotion rate doesn't drop after full gc. In the log you
commented the GC that took place at 1992 seconds was the last "quick"
minor GC. Bellow there's link to the gc log and jstat with the whole
information.

I'll try to test -XX:+NeverPromote.

*GC/Jstat Output*
https://drive.google.com/file/d/0B-jeSacHbFsJQ3VUZHlLalRuQzA/edit?usp=sharing

*Print GC Jconsole*
https://drive.google.com/file/d/0B-jeSacHbFsJcTFnb1pxMENVYzg/edit?usp=sharing

I really appreciate the support and time of all of you.

Regards,
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mail.openjdk.java.net/pipermail/hotspot-gc-use/attachments/20131220/3f9d17ee/attachment-0001.html