is it correct Heap Structure on basis of given JVM Parameters ?

[Мамонтов Иван]

I think it will be very useful to add the following flags:

   - -XX:+PrintCommandLineFlags Print flags specified on command line or
   set by ergonomics
   - -XX:+PrintVMOptions Print flags that appeared on the command line
   - -XX:+PrintFlagsFinal Print all VM flags after argument
   and ergonomic processing

This will avoid problems with implicit VM options.

java -XX:+PrintVMOptions -XX:+PrintCommandLineFlags -XX:+PrintFlagsFinal
-version

VM option '+PrintFlagsFinal'

VM option '+PrintVMOptions'

VM option '+PrintCommandLineFlags'

-XX:InitialHeapSize=262900032 -XX:MaxHeapSize=4206400512
-XX:ParallelGCThreads=4 -XX:+PrintCommandLineFlags -XX:+PrintFlagsFinal
-XX:+PrintVMOptions -XX:+UseCompressedOops -XX:+UseParallelGC

[Global flags]

    uintx AdaptivePermSizeWeight                    = 20
 {product}

    uintx AdaptiveSizeDecrementScaleFactor          = 4
{product}

    uintx AdaptiveSizeMajorGCDecayTimeScale         = 10
 {product}

    uintx AdaptiveSizePausePolicy                   = 0
{product}

...

java version "1.6.0_45"

Java(TM) SE Runtime Environment (build 1.6.0_45-b06)

Java HotSpot(TM) 64-Bit Server VM (build 20.45-b01, mixed mode)

It works on java from 1.6.0_30 to 1.7.0_45.


2014-04-30 6:16 GMT+04:00 Jon Masamitsu <jon.masamitsu at oracle.com>:

>  Vipin,
>
> If you want to see the heap after it has fully expanded, use -Xms2048m
> (not -Xms32m) and
> -XX:NewSize=64m (not -XX:NewSize=8m) and add -XX:PrintGCDetails -version
> to your java
> command line.  You'll see something like this
>
>  $JAVA_HOME/bin/java  -XX:+PrintGCDetails -Xms2048m -XX:NewSize=64m
> -XX:NewRatio=2  -XX:MaxNewSize=64m -XX:SurvivorRatio=25  -Xmx2048m  -version
> java version "1.7.0"
> Java(TM) SE Runtime Environment (build 1.7.0-b147)
> Java HotSpot(TM) Server VM (build 21.0-b17, mixed mode)
> Heap
>  PSYoungGen      total 63168K, used 2432K [0xf7c00000, 0xfbc00000,
> 0xfbc00000)
>   eden space 60800K, 4% used [0xf7c00000,0xf7e600d0,0xfb760000)
>   from space 2368K, 0% used [0xfb9b0000,0xfb9b0000,0xfbc00000)
>   to   space 2368K, 0% used [0xfb760000,0xfb760000,0xfb9b0000)
>  PSOldGen        total 2031616K, used 0K [0x7bc00000, 0xf7c00000,
> 0xf7c00000)
>   object space 2031616K, 0% used [0x7bc00000,0x7bc00000,0xf7c00000)
>  PSPermGen       total 16384K, used 1356K [0x77c00000, 0x78c00000,
> 0x7bc00000)
>   object space 16384K, 8% used [0x77c00000,0x77d532d0,0x78c00000)
>
> Jon
>
>
>
> On 4/29/2014 2:54 AM, Sharma, Vipin K wrote:
>
>  HI All
>
>
>
> In my Java application ( JDK 7) JVM parameters are
>
> -Xms32m -Xmx2048m -Xss1m -XX:+UseParallelGC -XX:NewRatio=2 -XX:NewSize=8m
> -XX:MaxNewSize=64m -XX:SurvivorRatio=25 -XX:+UseAdaptiveSizePolicy
>
>
>
> Xmx2048m                          :  Maximum Heap memory is 2GB
>
> MaxNewSize=64m          :  Maximum Young Generation Size 64 MB
>
> NewRatio=2                       :  Old Generation Size will be double of
> Young generation size so Maximum Old generation Size will be 64*2
>
>
>
> As per my understanding below will be Heap structure when all parts of
> heap are allocated maximum memory
>
> Young(64 M )     + Old ( 128 M)    + Rest Memory only for Permanent
> Generation Area
>
>
>
> I feel we are not using heap memory efficiently more than 1.8 GB is
> allocated for Permanent Generation only.
>
> Is it correct understanding ? if not then what will be heap structure in
> case we give max memory to all parts?
>
>
>
>
>
> Thanks,
>
> Vipin Sharma
>
>
> _______________________________________________
> hotspot-gc-use mailing listhotspot-gc-use at openjdk.java.nethttp://mail.openjdk.java.net/mailman/listinfo/hotspot-gc-use
>
>
>
> _______________________________________________
> hotspot-gc-use mailing list
> hotspot-gc-use at openjdk.java.net
> http://mail.openjdk.java.net/mailman/listinfo/hotspot-gc-use
>
>


-- 
Thanks,
Ivan
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.openjdk.java.net/pipermail/hotspot-gc-use/attachments/20140501/5a06ebef/attachment.html>