We are using Tomcat 5.5 to run high load through our servlets for about
24 hours. The tests run a constant load and repeat the same set of
tests over and over. We are using perf mon to keep an eye on various
counters in Tomcat.
We find after about 8 hours, we see this huge jump in thread count,
memory and handles inside Tomcat. All at once, we about double these
values. This happens over a very short time span, just a few minutes.
We don't drop back down to our old levels, but continue on at these new
levels without gaining and then another jump will occur about 6 hours
later (the time span is not consistent). That graph of threads, total
mem and handles for this behavior looks like a staircase.
Looking at logs from our servlets, there is no unexpected behavior
during these huge jumps. They are chugging along handling the traffic
as expected and don't have any delays or out of the ordinary behavior.
Does this sound like a GC issue? these are the settings we invoke TC
with.
JAVA_OPTS="-server -Xmx1024M -XX:+UseConcMarkSweepGC -XX:+UseParNewGC
-XX:ThreadStackSize=512"
What is the best tool we can use to gather better information around the
problem, both free and for fee?
thank you,
Neil
