Path: utzoo!news-server.csri.toronto.edu!rutgers!usc!rpi!zaphod.mps.ohio-state.edu!caen!kuhub.cc.ukans.edu!markv
From: markv@kuhub.cc.ukans.edu
Newsgroups: comp.sys.amiga.programmer
Subject: Re: The case of the vanishing memory
Message-ID: <29032.27dcb506@kuhub.cc.ukans.edu>
Date: 12 Mar 91 17:01:26 GMT
References: <1991Mar12.070655.1515@zorch.SF-Bay.ORG>
Organization: University of Kansas Academic Computing Services
Lines: 62

In article <1991Mar12.070655.1515@zorch.SF-Bay.ORG>, mike@zorch.SF-Bay.ORG (Mike Smithwick) writes:
> ["Share and enjoy! Share and enjoy! Our plastic girls and plastic boys!"]
> 
> I have noticed that when I open a window, then procede to create an event in
>  said window (MOUSEMOVE, clicking on a gadget, etc), sometimes I'll 
> loose 56 bytes, sometimes.

But you get it back when you close the window, right?
 
> Ok, so I assume that this is my IntuiMessage (52 bytes + 4 bytes overhead?).
> But it is not consistant. It only happens early in the window's life. I can
> generate events like crazy, but after a while, the memory loss will stop.

Yes, that's correct...
 
> This is very sporadic, and the events that appear to be eating away at 
> the memory still get through for me to process and reply to. So its not
> like I am ignoring them or anything, but it does seem to have something
> to do with how quickly I can get to process them. 

Very good...
 
> This only happens on my slow (read 68000) machines. On my 020 A1000 and
> A3000 it doesn't happen.

Your catching on...
 
> So anybody have any idears?

Yes.  Intuition maintains a list of IntuiMsgs allocated for each IDCMP
port.  When Intuition needs a message, it checks this list.  If one is
available, it uses it, otherwise it turns around and allocates it from
the system, then sends it.  When you finally reply a msg, Intition
does NOT return it to the system, it tacks it onto the free list of
msgs.  When the IDCMP port finally goes away (via CloseWindow() or
ModifyIDCMP(xx,NULL) ), Intuition releases the messages.

So, as long as you fall behind processing the messages, Intuition will
keep grabbing memory from the system for more msgs.  Eventually, the
pool gets to the point where there are enough msgs and it mostly quits
running out.

On faster machines, you program gets more done, and processes the msgs
faster, so the backlog stays a lot shorter.

There is no way to prevent Intuition from doing this, but for most
cases you won't use enough messages to gobble enough memory to cause
problems.  The exception is things like FOLLOWMOUSE which can create
massive amounts msgs very quickly.  

In general the best be is to rip through messages as quickly as
possible.  Dont be afraid to use ModifyIDCMP() to shut off some
messages if your going to go off into space for a while.
-- 
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Mark Gooderum			Only...		\    Good Cheer !!!
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