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From Chris Burroughs <>
Subject Re: Minor Follow-up: reduced cached mem; resident set size growth
Date Wed, 06 Apr 2011 16:32:57 GMT
On 04/05/2011 04:38 PM, Peter Schuller wrote:
>> - Different collectors: -XX:+UseParallelGC -XX:+UseParallelOldGC
> Unless you also removed the -XX:+UseConcMarkSweepGC I *think* it takes
> precedence, so that the above options would have no effect. I didn't
> test. In either case, did you definitely confirm CMS was no longer
> being used? (Should be pretty obvious if you ran with
> -XX:+PrintGCDetails which looks plenty different w/o CMS)

More precisely, I did this:

# GC tuning options
#JVM_OPTS="$JVM_OPTS -XX:+UseConcMarkSweepGC"
#JVM_OPTS="$JVM_OPTS -XX:+CMSParallelRemarkEnabled"
#JVM_OPTS="$JVM_OPTS -XX:SurvivorRatio=8"
#JVM_OPTS="$JVM_OPTS -XX:MaxTenuringThreshold=1"
#JVM_OPTS="$JVM_OPTS -XX:CMSInitiatingOccupancyFraction=75"
#JVM_OPTS="$JVM_OPTS -XX:+UseCMSInitiatingOccupancyOnly"
JVM_OPTS="$JVM_OPTS -XX:+UseParallelOldGC"

>> I have gc logs if anyone is interested.
> Yes :)

By "have gc logs" I meant "had them until I accidental blew them away
while restarting a server".  Will post them in a day or two when there
is a reasonable amount of data or the quantum state collapses and the
problem vanishes when it is observed.

>> [1]
> I did go back and revisit the old thread... maybe I'm missing
> something, but just to be real sure:
> What does the "no color"/white mean on this graph? Is that application
> memory (resident set)?
> I'm not really sure what I'm looking for since you already said you
> tested with 'standard' which rules out the
> resident-set-memory-as-a-result-of-mmap being counted towards the
> leak. But still.

I will be the first to admit that Zabbix's graphs are not the... easiest
to read.  My interpretation is that no "color" is "none of the above"
and by being unavailable is thus in use by applications.  This fits with
what I see will free and measurements of the RSS of the jvm from /proc/.
 I'll leave free -s going for a few days while waiting on the gc logs as
an extra sanity test.  That's probably easier to reason about anyway.

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