forum.vdsworld.com

[gonzabar]

Dos anyone knows why a program with defined functions "eat" more and more memory of system. Examples:

Program-1:

[CodeScript]

Yes It does cause memory leak both on Xp and Win 98.
Shifting #DEFINE to the top doesnot help.
Loss is slower with "Gloabl variables" but it may simply be that they are slower
Any clues

[Skit3000]

Maybe it's because the VDS interpreter has to seek for some defined commands and functions, next to the ones it normally seeks for? I'm almost 100% sure that the variables aren't the problem, because they are all changed into a global variable when compiled (that's why there is a limited number of variables available)...

[jules]

I'll look into it but I don't think @sysinfo(freemem) is a valid way to test for a memory leak because the Windows memory manager doesn't give back to the system every block of memory the instant a program frees it. That would be inefficient. Instead, it waits until a lot of memory is needed and then consolidates all the memory that has been freed into a block and adds it to the free memory pool. So what you're seeing is because the VDS interpreter allocates and then frees a block of memory for the local variables and stuff each time a function is called, which it doesn't do if you use a gosub.

[gonzabar]

I have observed that the program (interpreted or compiled) no frees the blocks of memory allocated for local variables and stuff each time the function is called. If you run the program and wait (infinte loop), the amount of free memory is, finally, zero bytes.

[jules]

Well, you are right (though I'm interested to know how you worked out what the leaked memory blocks were without the benefit of the VDS source code. ) I always thought that Delphi was supposed to take care of the memory management of strings by itself, but obviously it doesn't.

[bbelcher]

I found a part solution to the memory leak issue. What I found is so simple it's stupid. If you’re running a dialog with your app all you have to do is minimize it. Window iconize doesn’t seam to work. But if you click on the minimize button the app will release the memory and start all over again. I'm betting there is a @sendmsg that you could send to the window to do something similar it might not even have to be a minimize funshion. who knows maybe a repaint would do it.

[Boo]

This goes back to my recent posting(s) as follows:

http://forum.vdsworld.com/viewtopic.php?p=22644&highlight=#22644

When running my program, and after minimizing it as explained by Bbelcher, this FIXED the massive memory issue. I hope someone can figure out a way to accomplish this without having to click on the application's minimize button each time...

FYI: My application includes a lot of defined functions/commands...

Cheers,

- Boo

[jules]

The issue with user defined commands and functions was a bug in VDS 5 that was fixed in the 5.01 update.

What's happening when you minimize an application is nothing to do with VDS, which doesn't even know if the app has been minimized or not. It's probably something to do with Windows freeing up the graphical resources used to display the application on screen, that are no longer needed when it isn't there any more.

Window iconize just sends a message to the window to minimize it, so I doubt if there is anything extra you can do using @sendmsg. I don't really see why it's a problem, since you don't appear to have a memory leak (which is when an app constantly uses more and more memory until Windows grinds to a halt.)

[bbelcher]

Jules,

I do have an app that keeps using more and more resources. Basically I'm using PGWARES VDSIPP dll to run a TFTP server and client. The TFTP server will keep climbing every time the TFTP client requests a download. If I run it in a loop I can easily get 30 Megs of memory use for the TFTP server portion. The TFTP server portion does not have a dialog. If I add a dialog then the minimize button on the dialog will release all that memory and it will start again at about 3 meg.

Here is some code that I'm useing.

[jules]

How do you know it isn't the extension that's using the memory?

I have written dozens of utilities in VDS 5, many of which are designed to run all day long as system tray applications. I use them myself, and they have been downloaded and run by tens of thousands of people. I have never noticed, nor been told about, any tendency for these applications to eat memory.

The fact that the memory used appears to be reallocated when you minimize the window suggests that it is some Windows mechanism that causes this to happen. Because your app is using an external subsystem (Winsock) it may be that Windows decides that it's safe to do a memory cleanup when the app is minimized, since this may indicate that it is temprarily not being used.

There is a problem with TCP/IP under Windows in that you need a window to receive messages notifying the program of events. I use the VDS Internet Suite for my TCP apps, which as far as possible works synchronously and uses polling to avoid this. However, it does require a VDS window to be created in order to receive messages informing about connection attempts, if you want to implement a server.

The closest app I have to yours (using VDS Internet Suite) is StopAds, which blocks ads and other malicious sites by using a hosts file to reroute accesses to localhost, which serves a blank page using a tiny VDS-written web server. When I used Internet Explorer this server got hundreds of requests a day, but I have never noticed an extreme memory usage, nor have any of the other users. (Since I switched to Firefox it doesn't get much work: so far today it's blocked just 19 accesses!)

[PGWARE]

It could be the dll actually consuming the memory, I'm not certain if this is the case or not unless what you posted is the entire of your code.

I do have one question:

[bbelcher]

Thanks for the correction PGWARE. I wasn’t sure if that would work or not. I could use a different port that’s not a big deal to me. What I'm going for is the fastest possible way to support up to a 1000 clients without a possibility of losing any download request due to the 10 second timeout period. Any Ideas.


Jules,
I'm not sure exactly what’s going on but I do appreciate all the ideas. I think what I'm going to do is put a timer above the wait event and if it reaches say 5 minutes without an event then start another instance of the TFTP helper app and kill the old one. I believe this should work.

[PGWARE]

Hello,
The 10 second timeout period only occurs when a 'ONGETFILEREQUEST ' event is triggered. Which gives YOU up to 10 seconds to respond with the command> INTERNET TFTP-SERVER,ALLOWTRANSFER,1,<value of yes/no>,<filename> to tell it either YES allow the download or NO do not allow download; as long as you respond fast enough there is no delay at all.

You should be able to setup something like this:

[Boo]

See this posting for a solution to this problem:

http://www.vdsworld.com/forum/viewtopic.php?t=1253

Cheers,

- Boo