GC Tuning

[Bernd]

Josef, the -XX:MaxGCPauseMillis=100 is only a hint to the GC to aim
for those pause times. You will not get a gurantee (and typically
100ms is a limit you can only reach on highly specialized setups
(small heap, low occupancy setings, etc). In fact it has been reported
that aiming too low for this target can even hurt.

Gruss
Bernd

2015-09-18 13:06 GMT+02:00 Joseph <josephj at arssoftware.com>:
> Hi Tao,
>
>
>
> Thank you for your quick response.
>
>
>
> I am trying to tune the No SQL database which require real time response.
> Here in some cases server not responding due to the garbage pauses. Maximum
> response pause allowed is below or equal to 100. When I set
> -XX:MaxGCPauseMillis=100 flag, each collection pause exceeds  at most of
> 100 milliseconds?. I want reduce the total pause time maximum of  100
> milliseconds . Because server needs to respond within milliseconds.
>
>
>
>
>
> Regards
>
> Joseph
>
>
>
> From: Tao Mao [mailto:yiyeguhu at gmail.com]
> Sent: Friday, September 18, 2015 2:21 AM
> To: Joseph James
> Cc: hotspot-gc-use
> Subject: Re: GC Tuning
>
>
>
> Hi,
>
>
>
> What's the goal here (latency or throughput)? What's the bottom line now?
>
>
>
> Thanks.
>
> Tao Mao
>
>
>
>
>
> On Thu, Sep 17, 2015 at 6:02 AM, Joseph <josephj at arssoftware.com> wrote:
>
> Hi ,
>
>
>
> I am Joseph. I am trying to tune performance of  our server .I run server
> with following g1 gc options.
>
>
>
> Maximum heap allocated to server is 5GB.
>
>
>
> “ -XX:+UseG1GC -XX:MaxGCPauseMillis=100 -XX:ParallelGCThreads=4
> -XX:InitiatingHeapOccupancyPercent=65 -XX:+ParallelRefProcEnabled
> -XX:-ResizePLAB -Xloggc:/var/log/hbase/gc-hbase.log -XX:+PrintGCDetails
> -XX:+PrintAdaptiveSizePolicy -XX:+PrintGCTimeStamps”
>
>
>
> The gc logs resulted with above gc flags are attached with the mail.How to
> reduce garbage pause time in our server.
>
>
>
> Thank you for your valuble time
>
>
>
>
>
> Regards,
>
> Joseph
>
>
>
>
>
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