Re: NetBean become very slow ...

Lew <>
Thu, 11 Oct 2007 12:13:03 -0400
Eric Sosman wrote:

Ahan Hsieh wrote:

Hi, All:
    Recently I'm using the Sun NetBean IDE 5.5.1 in Windows, and I found
it'll become very slowing when long time no operation then open it.
In task manager if long time no use then use the NetBean, the memory will
become low;
then open NetBean it increase the memory and diffucult to use the editor.
    Fianlly it up to near 150M, then operation is smooth, would you
tell me
what happend and how to avoid the memory decreasing ?

    It sounds like Windows has decided to steal RAM away from
the idle NetBeans process and move its contents to the paging
disk. When you reactivate the process, there's a page fault
and a disk I/O whenever it tries to access a swapped-out page.
If a lot of memory was paged out, there will be a lot of page-in
I/O's before it's RAM-resident again -- and since a disk access
is on the order of a hundred thousand times slower than a RAM
access, NetBeans runs slowly until it's got its memory back.

OTOH, if NetBeans is actually releasing the memory, go into the
$NETBEANS_HOME/etc/netbeans.conf file and increase the "-J-Xms" parameter.

For example, my netbeans.conf sets:

  -J-server -J-Xms32m -J-XX:PermSize=32m -J-XX:MaxPermSize 0m -J-ea
  -J-Dapple.laf.useScreenMenuBar=true -J-XX:+UseConcMarkSweepGC
  -J-XX:+CMSClassUnloadingEnabled -J-XX:+CMSPermGenSweepingEnabled"

(In the file this is all one line, wrapped here for Usenet.)

Perhaps you want to set -J-Xms64m or higher.

If Eric's assessment is correct, though, then this won't help.


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