lkml.org 
[lkml]   [2005]   [Oct]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    SubjectRe: The "best" value of HZ
    Date
    On Fri, 28 Oct 2005 02:00 pm, Jesper Juhl wrote:
    > On 10/28/05, Lee Revell <rlrevell@joe-job.com> wrote:
    > > On Fri, 2005-10-28 at 03:31 +0100, Alistair John Strachan wrote:
    > > > On Friday 28 October 2005 00:18, Claudio Scordino wrote:
    > > > > Hi,
    > > > >
    > > > > during the last years there has been a lot of discussion about
    > > > > the "best" value of HZ... On i386 was 100, then became 1000, and
    > > > > finally was set to 250. I'm thinking to do an evaluation of this
    > > > > parameter using different architectures.
    > > > >
    > > > > Has anybody thought to give the possibility to modify the value of HZ
    > > > > at boot time instead of at compile time ? This would allow to easily
    > > > > test different values on different machines and create a table
    > > > > containing the "best" value for each architecture... At this moment,
    > > > > instead, we have to recompile the kernel for each different value :(
    > > > >
    > > > > Do you think there would be much work to do that ?
    > > > > Do you think it would be a desired feature the knowledge of the best
    > > > > value for each architecture with more precision ?
    > > >
    > > > Google for "dynticks". There's obviously an overhead associated with HZ
    > > > not being a constant (the compiler cannot optimise many expressions),
    > > > but the feature is being worked on nonetheless.
    > >
    > > Well Linus had the best idea in that thread (as usual) which was to
    > > implement "dynamic ticks" by leaving HZ a constant, setting it to a high
    > > value, and skipping ticks when idle. Has there been any work in that
    > > direction?
    >
    > i did a bit of work in that area, but the stuff I came up with never
    > seemed to work right, so I dropped it.

    It's all still in development at the moment but not far from being available
    again. We stood back a bit to make some structural changes before trying to
    make it ready for prime time.

    Cheers,
    Con
    -
    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: 2005-10-28 06:35    [W:0.023 / U:0.040 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site