Not quite

You've heard of malloc and friends? The heap is the area where they assign you memory in.

[link|http://www.memorymanagement.org/glossary/h.html#heap|http://www.memoryman...ssary/h.html#heap]

Frequently (but not always) the addresses that you'll find for the heap start at one end of your address space and the stack starts at the other. The two grow together. (Should they meet, you'll have problems...)

Note that the addresses your program sees data at bear only a tenuous relationship to where the data really is. There is a mapping between the physical location and the virtual one which is maintained by the operating system. (For instance after a fork your memory is all marked copy on write. As you write to them, memory pages get copied and your mapping is updated so that what you see as location X all of a sudden is somewhere else - and you don't know.)

From the description that you gave, it seems likely that the setting you are playing with controls the amount of data that Java can create and manipulate. Make it bigger, and Java is allowed to take more memory up so can do more things.

Cheers,
Ben

Post #148,892 by ben_tilly 3/26/04 10:09:48 PM 3/26/04 10:11:04 PM Reply	Not quite You've heard of malloc and friends? The heap is the area where they assign you memory in. [link\|http://www.memorymanagement.org/glossary/h.html#heap\|http://www.memoryman...ssary/h.html#heap] Frequently (but not always) the addresses that you'll find for the heap start at one end of your address space and the stack starts at the other. The two grow together. (Should they meet, you'll have problems...) Note that the addresses your program sees data at bear only a tenuous relationship to where the data really is. There is a mapping between the physical location and the virtual one which is maintained by the operating system. (For instance after a fork your memory is all marked copy on write. As you write to them, memory pages get copied and your mapping is updated so that what you see as location X all of a sudden is somewhere else - and you don't know.) From the description that you gave, it seems likely that the setting you are playing with controls the amount of data that Java can create and manipulate. Make it bigger, and Java is allowed to take more memory up so can do more things. Cheers, Ben "good ideas and bad code build communities, the other three combinations do not" - [link\|http://archives.real-time.com/pipermail/cocoon-devel/2000-October/003023.html\|Stefano Mazzocchi] Edited by ben_tilly March 26, 2004, 10:11:04 PM EST Expand All History
Post #148,905 by boxley 3/26/04 11:01:53 PM Reply	the only problem is From the description that you gave, it seems likely that the setting you are playing with controls the amount of data that Java can create and manipulate. Make it bigger, and Java is allowed to take more memory up so can do more things. it is doing a lot less, constant session expired messages, put the old lower values in and rekicked, all better but has different issues. thanx, bill In Bush\ufffds America, fighting terrorism abroad is used as a pretext for vanquishing civil liberties at home. David Podvin questions, help? [link\|mailto:pappas@catholic.org\|email pappas at catholic.org]
Post #149,045 by ben_tilly 3/28/04 2:09:29 AM Reply	I don't know why it would become borked Perhaps a shitty GC algorithm slowed down having to handle more data? So you can store more data, but have less CPU. Perhaps something else began thrashing? I know that at one point threads were very heavy-weight on HP-UX. If that is still true (or is just true of your machine), then Java would strike me as pretty much as worst-case disaster. Enabling more threads to fit in the Java process might be a Bad Thing. I can guess endlessly. Some of my guesses might even get near the mark. But the fact is that I don't know, and you're the one who has to deal with it. Good luck, Ben "good ideas and bad code build communities, the other three combinations do not" - [link\|http://archives.real-time.com/pipermail/cocoon-devel/2000-October/003023.html\|Stefano Mazzocchi]
Post #149,089 by boxley 3/28/04 10:55:33 AM Reply	All of your guesses are for me to follow up in areas I was not able to consider, so thanks much bill In Bush\ufffds America, fighting terrorism abroad is used as a pretext for vanquishing civil liberties at home. David Podvin questions, help? [link\|mailto:pappas@catholic.org\|email pappas at catholic.org]
Post #149,175 by ben_tilly 3/29/04 10:36:30 AM Reply	One other thing to follow up on... Massively increasing the parameter seems to have lead to thrashing of some sort. Somewhere between where it is now and where you put it caused it to thrash. Play around with it. A modest increase might help the current problems without getting you into thrash territory. Cheers, Ben "good ideas and bad code build communities, the other three combinations do not" - [link\|http://archives.real-time.com/pipermail/cocoon-devel/2000-October/003023.html\|Stefano Mazzocchi]
Post #149,176 by admin 3/29/04 10:39:58 AM Reply	That will happen if the heap size is > available memory We did that to a web server here once. :-) Regards, -scott anderson "Welcome to Rivendell, Mr. Anderson..."
Post #149,189 by ben_tilly 3/29/04 11:07:42 AM Reply	Did you read the whole thread, carefully? Particularly [link\|http://z.iwethey.org/forums/render/content/show?contentid=148776\|this one]? boxley seems to have ruled that out, else it would have been my first thought. Cheers, Ben "good ideas and bad code build communities, the other three combinations do not" - [link\|http://archives.real-time.com/pipermail/cocoon-devel/2000-October/003023.html\|Stefano Mazzocchi]
Post #149,220 by admin 3/29/04 2:22:33 PM Reply	Nope, but doesn't invalidate my comment. :-) It just isn't particularly useful for Bill. ;-) Regards, -scott anderson "Welcome to Rivendell, Mr. Anderson..."
Post #149,203 by boxley 3/29/04 11:51:48 AM Reply	playing with slight increments gives mucky mucks heartburn "You're just like me streak. You never left the free-fire zone.You think aspirins and meetings and cold showers are going to clean out your head. What you want is God's permission to paint the trees with the bad guys. That wont happen big mon." Clete questions, help? [link\|mailto:pappas@catholic.org\|email pappas at catholic.org]
Post #149,716 by CRConrad 4/1/04 2:49:50 PM Reply	Stupid muckers - tell them "This is how it's done, so STFU."

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