RE: javaw Slowdown

[michael@xxxxxxxxxxxxxxxxxx]

thanks Scott...more knowledge is always better than less...

> -------- Original Message --------
> Subject: RE: [WDSCI-L] javaw Slowdown
> From: Scott Klement <wdsci-l@xxxxxxxxxxxxxxxx>
> Date: Wed, November 09, 2005 1:07 pm
> To: Websphere Development Studio Client for iSeries
> <wdsci-l@xxxxxxxxxxxx>
> 
> > I think it might, though I haven't seen it in the last couple of lockups
> > (since I received your email). Something else I noticed in other lockups
> > today is that if I ALT-TAB to another window, and then back to WDSC, the
> > whole WDSC window is white.
> 
> Windows programs sit on a message queue waiting for information from 
> Windows.  When the messages are received, they carry out instructions.  A 
> message from Windows might be "redraw part of the window" or "minimize" or 
> "a key was pressed" or "the mouse was clicked".  So, the prgorams entire 
> interaction with the user and the screen is based on this message queue.
> 
> If the program gets busy doing other things (like, it gets stuck in a 
> loop, or it's busy doing some sort of disk access or calculation or 
> whatever) then it never reads this message queue, and never gets the 
> message that tells it that it has to re-draw part of it's screen.
> 
> This is when you get an area of the screen that's "white".  (or, sometimes 
> it looks like part of the window that had overlaid it).  Because the 
> program is busy with something else and not carrying out the instructions 
> from Windows.
> 
> Since you see that "javaw.exe" is taking up lots of CPU, I'd guess that 
> WDSC is getting stuck in a loop or is doing something that's very resource 
> intensive.
> 
> Everything for WDSC will show as "jawaw.exe" because Java programs don't 
> run directly on the computer's hardware. They run through the Java Virtual 
> Machine.  It's that virtual machine that runs directly on the computer's 
> hardware.  So when you see "javaw.exe" what you're really seeing is that 
> the JVM is taking up lots of CPU.  Unfortunately, it doesn't tell you what 
> program is at fault, since you can potentially have lots of Java programs 
> running at once.
> 
> I know, none of this helps you solve your problem... just thought the info 
> might be interesting or helpful in some way.
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