test fork

17 Nov 2003

      Joey,

	I have a very simple c program that you can use to test your fork

limit.

Set your max proc per uid to some number (say 200),

set your shell ulimit -u

then do a ps -U you | wc -l to see how many procs you currently have

under your username.

run ./test_fork xxx, so that you end up bumping up to or just over your

max proc limit.

The idea is to play around with the numbers to verify that your

maxprocperuid setting is taking hold. If it all works as planned, then

at least you can rule out one source of the problem.

After 20 seconds, the children processes will die off, and your account

will be usable again.

#include <stdlib.h>

#include <stdio.h>

#include <sys/types.h>

#include <unistd.h>

int main(int argc, char * argv[])

	{

	int counter = 0;

	int max = 0;

	int number_forked = 0;

	pid_t pid;

	if (argc < 2)

		{

		printf ("You must specify number of children to fork\n");

		exit (-1);

		}

	max = atoi(argv[1]);

	for (counter = 0; counter < max; counter ++)

	{

		pid = fork();

		if (pid == 0)

			{

			/* We are in the child, sleep away

			 * Don't sleep for too long, so we don't lock up

			 * the account for an extended period of time

			 */

			sleep(20);

			}

		else if (pid != -1)

			{

			number_forked++;

			printf ("Child pid is %d, count is %d\n", pid, counter);

			}

	}

	printf ("Number of successful forks is %d\n", number_forked);

}

Anyway, hope that is of some help

-Brian T

On Nov 16, 2003, at 11:14 PM, Joey Stanford wrote:
...
Hi Brian!
...

...
Here you go...  Don't think it would be much help though..
...

...
[joey@futune]:/Users/joey>ulimit -a
...
core file size        (blocks, -c) 0
...
data seg size         (kbytes, -d) unlimited
...
file size             (blocks, -f) unlimited
...
max locked memory     (kbytes, -l) unlimited
...
max memory size       (kbytes, -m) unlimited
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open files                    (-n) 10240
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pipe size          (512 bytes, -p) 1
...
stack size            (kbytes, -s) 65536
...
cpu time             (seconds, -t) unlimited
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max user processes            (-u) 512
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virtual memory        (kbytes, -v) 9007199254806527
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[joey@futune]:/Users/joey>
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...

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On Nov 16, 2003, at 10:06 PM, Brian Tabone wrote:
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Joey,
...
...
...
...
I was re-reading your message and noticed you had already tried
...
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maxprocperuid, my bad. However, What does
...
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bash> ulimit -a
...
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Say on your machine, on mine, even though ulimit says unlimited,
...
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ulimit -a tells me
...
...
...
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ulimit -a
...
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core file size        (blocks, -c) 0
...
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data seg size         (kbytes, -d) 6144
...
...
file size             (blocks, -f) unlimited
...
...
max locked memory     (kbytes, -l) unlimited
...
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max memory size       (kbytes, -m) unlimited
...
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open files                    (-n) 1024
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pipe size          (512 bytes, -p) 1
...
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stack size            (kbytes, -s) 8192
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cpu time             (seconds, -t) unlimited
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max user processes            (-u) 100
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virtual memory        (kbytes, -v) 14336
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I think you have to explicitly bump up your ulimit in your shell
...
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-Brian T
...
...
On Nov 16, 2003, at 8:32 PM, Joey Stanford wrote:
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Howdy!
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I'm out of options, hoping you guys (and girls) might be able to clue
...
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me in.
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...
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Running 10.3 will all the latest updates on a 2ghz, 2gig Dual G5.
...
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Using tcsh but bash has same problem.
...
...
...
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I keep running out of "resources" whatever that is when I hit about
...
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135
...
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pids (and I have over 100gig of disk left and about 500meg of unused
...
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memory when this happens).  I get the standard "unable to fork"
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errors.
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e.g.
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2003-11-14 10:56:20.479 Konfabulator[6491] Exception raised during
...
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posting of notification.  Ignored.  exception: couldn't fork
...
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2003-11-14 16:18:14.697 Mail[1770] Exception raised during posting of
...
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notification.  Ignored.  exception: couldn't fork
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In term I get just "unable to fork"
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I bumped up my sysctl using /etc/sysctl.conf:
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kern.maxproc=2048
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kern.maxprocperuid=512
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and then unlimited in the shell:
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[joey@futune]:/Applications/entropy/src> limit
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cputime         unlimited
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filesize        unlimited
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datasize        unlimited
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stacksize       65536 kbytes
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coredumpsize    unlimited
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memoryuse       unlimited
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descriptors     10240
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memorylocked    unlimited
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maxproc         512
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[joey@futune]:/Applications/entropy/src> lsof | wc -l
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394
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kern.maxfiles = 12288
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kern.maxfilesperproc = 10240
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Help? Any ideas?
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Thanks!
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