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    SubjectRe: forking
    On Tue, 20 Apr 1999, Greg Lindahl wrote:

    > > Ok then, we seem to be looking at a 2.2.x problem, what regarding, I
    > > don't know. It's not in 2.0.x (I've pushed my box into the 512 range on
    > > 2.0.36 and then received the "cannot fork"). Suggestions so far have
    > > been memory fragmentation and insufficient procs. Anyone else have
    > > ideas?
    >
    > Actually, I've always had a problem like this on 2.0.x. I have a
    > 64-node cluster, and I frequently run scripts which fork 128 processes
    > at a time. These scripts occasionally get 'cannot fork', with no
    > resource starvation evident... I wrote some test programs but wasn't
    > able to get a nice, repeatable behavior.
    >

    I get 501 on my system.

    #include <stdio.h>
    #include <unistd.h>
    #include <signal.h>
    #include <wait.h>

    void reap(int unused)
    {
    while(wait3(&unused, WNOHANG, NULL) != -1)
    ;
    }

    main()
    {
    int i = 0;
    (void)signal(SIGCHLD, reap);
    for(;;)
    {
    switch(fork())
    {
    case 0:
    pause();
    exit();
    case -1:
    kill(-1, SIGINT);
    exit(1);
    default:
    fprintf(stderr,"Forks = %d\n", i++);
    }
    }
    return 0;
    }

    Cheers,
    Dick Johnson
    ***** FILE SYSTEM WAS MODIFIED *****
    Penguin : Linux version 2.2.6 on an i686 machine (400.59 BogoMips).
    Warning : It's hard to remain at the trailing edge of technology.


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