Messages in this thread | | | Date | Fri, 10 Nov 2006 10:03:03 +0100 | From | Pavel Machek <> | Subject | Re: 2048 CPUs [was: Re: New filesystem for Linux] |
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Hi!
> >>If some rogue threads (and it may not even be intetional) call the same > >>syscall stressing the one spinlock all the time, other syscalls needing > >>the same spinlock may stall. > > > >Fortunately, they'll unstall with probability of 1... so no, I do not > >think this is real problem. > > You can't tell that CPUs behave exactly probabilistically --- it may > happen that one gets out of the wait loop always too late.
Well, I don't need them to be _exactly_ probabilistical.
Anyway, if you have 2048 CPUs... you can perhaps get some non-broken ones.
> >If someone takes semaphore in syscall (we do), same problem may > >happen, right...? Without need for 2048 cpus. Maybe semaphores/mutexes > >are fair (or mostly fair) these days, but rwlocks may not be or > >something. > > Scheduler increases priority of sleeping process, so starving process > should be waken up first. But if there are so many processes, that >process
I do not think this is how Linux scheduler works. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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