Re: [RFC][PATCH 17/22] sched: add signaling overrunning -deadlinetasks.

[Raistlin]

On Thu, 2010-11-11 at 22:58 +0100, Peter Zijlstra wrote:
> On Fri, 2010-10-29 at 08:40 +0200, Raistlin wrote:
> > +static inline void __dl_signal(struct task_struct *tsk, int which)
> > +{
> > +       struct siginfo info;
> > +       long long amount = which == SF_SIG_DMISS ? tsk->dl.stats.last_dmiss :
> > +                          tsk->dl.stats.last_rorun;
> > +
> > +       info.si_signo = SIGXCPU;
> > +       info.si_errno = which;
> > +       info.si_code = SI_KERNEL;
> > +       info.si_pid = 0;
> > +       info.si_uid = 0;
> > +       info.si_value.sival_int = (int)amount;
> > +
> > +       /* Correctly take the locks on task's sighand */
> > +       __group_send_sig_info(SIGXCPU, &info, tsk);
> > +       /* Log what happened to dmesg */
> > +       printk(KERN_INFO "SCHED_DEADLINE: 0x%4x by %Ld [ns] in %d (%s)\n",
> > +              which, amount, task_pid_nr(tsk), tsk->comm);
> > +} 
> 
> This being a G-EDF like scheduler with a u<=1 schedulability test, we're
> firmly in soft-rt territory which means the above will be very easy to
> trigger.. Maybe not spam dmesg?
>
Ok, right. Maybe, if I add the SF_HARD_RT flag (and force the hard tasks
to run on a single CPU they must specify) I can keep the notification
for those tasks only. What do you think?

Thanks,
Dario

-- 
<<This happens because I choose it to happen!>> (Raistlin Majere)
----------------------------------------------------------------------
Dario Faggioli, ReTiS Lab, Scuola Superiore Sant'Anna, Pisa  (Italy)

http://blog.linux.it/raistlin / raistlin@xxxxxxxxx /
dario.faggioli@xxxxxxxxxx

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