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    SubjectRe: 2.6.13-rc6-rt9
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    Date
    On Sat, 2005-08-20 at 17:24 -0400, Jeff Dike wrote:
    > On Sat, Aug 20, 2005 at 09:27:25PM +0200, Peter Zijlstra wrote:
    > > Jeff, could you help us out here?
    > > What exactly does uml need to get out of the calibrate delay loop?
    >
    > Interrupts, it's not too demanding :-)
    >
    > If it's not seeing VTALRM, then it will never leave the calibration loop.
    >
    > Try stracing it and see what it's getting.

    Sorry for the late reply.

    Yes, that does seem to be the problem.

    Even with a current -rt (2.6.14-rc2-rt5) UML does not run. The issue is
    indeed (as jeff pointed out) that VTALRM is never send. The small test
    programm below illustrates this.

    On a non-rt kernel it completed in 1 second.
    On a -rt kernel it waits at infinitum.

    Kind regards,

    Peter Zijlstra

    ---------------------------

    #include <stdio.h>
    #include <stdlib.h>
    #include <unistd.h>
    #include <sys/time.h>
    #include <signal.h>

    volatile int quit = 0;

    void sig_vtalrm(int signr, siginfo_t * si, void * arg)
    {
    if (signr == SIGVTALRM) quit = 1;
    }

    int main()
    {
    struct itimerval ival = {{0,0}, {1, 0}};

    struct sigaction sa;
    sa.sa_sigaction = sig_vtalrm;
    sigemptyset(&sa.sa_mask);
    sa.sa_flags = 0;
    sigaction(SIGVTALRM, &sa, NULL);

    setitimer(ITIMER_VIRTUAL, &ival, NULL);

    printf("wait\n");
    while (!quit) ;
    printf("done\n");
    }


    --
    Peter Zijlstra <a.p.zijlstra@chello.nl>

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