Unable to fork process, no system resources available

Z

zmonster

Member
First of all, thank you for build 5582. All of my previous problems with Leopard have been solved by this update. I appreciate the hard work from Parallels, albeit 30 days late. :)

Second, I am still having a very serious problem with Parallels on Leopard. I find that if I leave Parallels running for 2-3 days (in single window mode), the app seems to use up all of the available Leopard kernel resources such that I cannot launch other application or open Terminal windows in Leopard. I am not a low-system kernel guy, so I'm not quite sure what's going on, but basically Parallels seems to be tying up the available set of kernel resources preventing 'fork' from spawing new processes.

Has anyone else noticed this major problem? Is it a known problem?

- Eric
 
Hello,

could you please tell me how much RAM do you have on your Mac?
Also please provide me with two screenshots?
1. 'Parallels Desktop' -> 'Preferences' -> 'Memory' tab.
2. 'Configuration Editor' -> 'Memory' tab.

After this problem occurs (i.e. you can not start any application) what will happen if you will shut down Parallels?

Best regards,
Stacey
 
maxprocperuid

Processor: 2.4 Ghz Intel Core 2 Duo
Memory: 4GB 667 MHz DDR2 SDRAM

Parallels Prefs: Adjust memory limit Automatically, enable VM preallocation NOT checked
Config Prefs: 384 MB (where optimal size is 512MB), 16MB video memory


Note that I don't think this is a memory issue. I am not running out of memory. I am running out of low-level Leopard kernel resources such that kernel 'fork' cannot function. I believe leopard has a max simultaneous process limit of 100. See:

http://lists.apple.com/archives/Xcode-users/2006/Jan/msg00945.html

The question is, what is happening in Parallels that spawns multiple processes (whereby they are possibly not being cleaned up and released back to the system)?

When the problem happens, shutting down Parallels usually returns my system back to normal for the most part. However, things are still a bit flaky until I reboot OSX (and that certainly fixes everything).

- Eric
 
Hello,

the performance of two Operating Systems may cause low kernel resources.
All virtualization software programs require quite a lot of kernel resources especially when run without rebooting for a long time.

Best regards,
Stacey
 
There's no way this issue is the 'normal' result of running two operating systems on the computer. If that were the case, Parallels would be out of business because it would be impossible to run two operating systems on a computer.

Some mechanism in Parallels is spawning processes using 'fork' on the Mac OS side of things such that after a couple of days in operation the number of running processes exceeds the limit set in the operating system. This is a big red flag that something is wrong. Obviously it is not happening to everyone, but I am sure other people must be experiencing this problem.

Something like this can happen if processes are not terminated properly after completion, for example. This can also happen if there's a looping bug in your software that incorrectly spawns dozens of processes when it was only supposed to spawn one process. These are just a few examples. I hope Parallels will do a review of their process related code to determine if there is indeed a problem. I believe there is.
 
If possible, leave Activity Monitor open and use Parallels until you again encounter this problem. Then go to the File menu in Activity Monitor and select "Save..." to save the list of processes (make sure that Activity Monitor is set to show all processes).
 
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As a follow up, I figured out what was wrong here. I have the Microsoft Mouse Driver installed on my Mac because I use a Microsoft Keyboard and Mouse. The Mouse Driver monitors the wireless mouse battery level, and if it is low, it will pop up an alert panel notifying you of the low level. Well, as it turns out, the fools at Microsoft fork a new process every time this window is opened, and they pop up the window CONTINUALLY (dozens of times). This is not only quite annoying, but it also consumes system fork resources.

Mac OSX is set to only allow 100 or so processes to run at a single time (you can increase this limit by changing a system config file...). Therefore, after the MS Mouse Driver ate up the available processes, Parallels could no longer fork the processes it needed and I ended up with this problem. In conclusion, this is NOT a bug in Parallels. I thank everyone for their input.
 
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