lkml.org 
[lkml]   [2004]   [Oct]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [ANNOUNCE] Linux 2.6 Real Time Kernel
    On Sat, Oct 09, 2004 at 03:30:27PM -0400, Lee Revell wrote:
    > On Sat, 2004-10-09 at 17:26, stefan.eletzhofer@eletztrick.de wrote:
    > > On Sat, Oct 09, 2004 at 02:30:28PM -0400, Lee Revell wrote:
    > > > On Sat, 2004-10-09 at 13:41, Karim Yaghmour wrote:
    > > > > Sven-Thorsten Dietrich wrote:
    > > > > > - Voluntary Preemption by Ingo Molnar
    > > > > > - IRQ thread patches by Scott Wood and Ingo Molnar
    > > > > > - BKL mutex patch by Ingo Molnar (with MV extensions)
    > > > > > - PMutex from Germany's Universitaet der Bundeswehr, Munich
    > > > > > - MontaVista mutex abstraction layer replacing spinlocks with mutexes
    > > > >
    > > > > To the best of my understanding, this still doesn't provide deterministic
    > > > > hard-real-time performance in Linux.
    > > >
    > > > Using only the VP+IRQ thread patch, I ran my RT app for 11 million
    > > > cycles yesterday, with a maximum delay of 190 usecs. How would this not
    > > > satisfy a 200 usec hard RT constraint?
    > >
    > > I think the keyword here is "deterministic", isn't it?
    >
    > Well, depends what you mean by deterministic. Some RT apps only require
    > an upper bound on response time. This is a form of determinism.

    Yes. But can you give that upper bound "a priori", that is w/o doing
    measurements with your application?

    Without that I think its impossible to get _guaranteed_ upper
    bounds, regardles of the application running. I think thats what
    "hard real-time" is all about.

    Stefan

    >
    > Lee
    >
    > -
    > 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/

    --
    Stefan Eletzhofer
    InQuant Data GBR
    http://www.inquant.de
    +49 (0) 751 35 44 112
    +49 (0) 171 23 24 529 (Mobil)
    +49 (0) 751 35 44 115 (FAX)
    -
    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/

    \
     
     \ /
      Last update: 2005-03-22 14:06    [W:0.024 / U:243.044 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site