Messages in this thread | | | From | "Jeff Merkey" <> | Subject | Re: priority inversion | Date | Fri, 30 Jul 1999 09:42:30 -0600 |
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Disagree. You can get into some pretty ugly starvation situations on a system with inversion. The "deadlocks" aren't really deadlocks at all, but cases where a process gets it's priority knocked down for so long everyone backs up behind it if it is holding mutexes. I've seen some pretty busted crap on older versions of Solaris (circa 1991) that used inversion models before they adopted inheritance. I agree that in most real world situations these problems don't show up, but there's always someone out there putting out apps that uses locks excessively. Folks might be splitting hairs here, but historically, this is the case folks make against inversion. It's an SMP problem almost exclusively and is tied to how priorities are managed in the kernel.
Jeff
----- Original Message ----- From: Marc Lehmann <pcg@goof.com> To: <linux-kernel@vger.rutgers.edu> Sent: Thursday, July 29, 1999 6:55 PM Subject: Re: priority inversion
> On Thu, Jul 29, 1999 at 11:50:55AM -0600, Jeff Merkey <jmerkey@timpanogas.com> wrote: > > Priority Inversion is **BAD BUSINESS**. Someone whould fix whatever this > > person is complaining about. I agree that priority inheritance is slow and > > makes for **FAT** sync object code, but it's either this or throw priorities > > out of the window in the kernel proper since we will see **LOTS** of > > deadlocks and busted applications if an inversion model is what we end up > > with. > > Linux has had this RT support for _quite_ some time. Other unices had as > well. It would be nice to have priority inheritance, but its by no means > as crucial as you describe it ;) > > -- > -----==- | > ----==-- _ | > ---==---(_)__ __ ____ __ Marc Lehmann +-- > --==---/ / _ \/ // /\ \/ / pcg@goof.com |e| > -=====/_/_//_/\_,_/ /_/\_\ XX11-RIPE --+ > The choice of a GNU generation | > | > > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.rutgers.edu > Please read the FAQ at http://www.tux.org/lkml/ >
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
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