incubator-cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Benjamin Black...@b3k.us>
Subject Re: GC options
Date Wed, 14 Apr 2010 06:35:24 GMT
FYI, G1 has been in 1.6 since u14.

2010/4/13 Peter Schüller <scode@spotify.com>:
>> I'm working on getting our latency as consistent as possible, and the gc likes to
kick off 60+ms periods of unavailability for a node, which for my application leads to a reasonable
number of timed out requests. Outside of the gc event, we get good responses.
>>
>> I'm happy with reduced throughput for shorter pauses, so I'm going to do the standard
jvm gc tuning guide[0] for short pauses, curious if anyone else has gone down this path and
gotten gc pauses consistent and low or if what's in bin/cassandra.in.sh is basically the best
I should expect. (Anyone tried jrockit?)
>
> If your situation is such that you are willing to use the unreleased
> JDK 1.7 and G1GC (still being marked as experimental and may still be
> a stability concern and since we are talking about storing data that
> probably means conservatism is called for) you can try that. It offers
> some more direct control over the target GC pause times, although does
> not provide guarantees. A potential starting point of VM options may
> be:
>
>         -XX:+UnlockExperimentalVMOptions
>         -XX:+UseG1GC
>         -XX:MaxGCPauseMillis=10
>         -XX:GCPauseIntervalMillis=15
>
> And maybe:
>
>         -XX:G1ConfidencePercent=100
>
> And maybe (not sure of current status but there used to be a known bug
> when enabled):
>
>         -XX:+G1ParallelRSetUpdatingEnabled
>         -XX:+G1ParallelRSetScanningEnabled
>
> --
> / Peter Schuller aka scode
>

Mime
View raw message