lkml.org 
[lkml]   [2005]   [Aug]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: 2.6.12 Performance problems


    --- Sven-Thorsten Dietrich <sven@mvista.com>
    wrote:

    > On Tue, 2005-08-23 at 10:10 -0700, Danial Thom
    > wrote:
    > >
    >
    > > > >Ok, well you'll have to explain this one:
    > > > >
    > > > >"Low latency comes at the cost of
    > decreased
    > > > >throughput - can't have both"
    > > > >
    > > > >
    > > > Configuring "preempt" gives lower latency,
    > > > because then
    > > > almost anything can be interrupted
    > (preempted).
    > > > You can then
    > > > get very quick responses to some things,
    > i.e.
    > > > interrupts and such.
    > >
    > > I think part of the problem is the continued
    > > misuse of the word "latency". Latency, in
    > > language terms, means "unexplained delay".
    >
    > latency
    >
    > n
    > 1: (computer science) the time it takes for a
    > specific block of data on
    > a data track to rotate around to the read/write
    > head [syn: rotational
    > latency]
    > 2: the time that elapses between a stimulus and
    > the response to it [syn:
    > reaction time, response time, latent period]
    > 3: the state of being not yet evident or active
    >
    > No apparent references to "unexplained" in
    > association with the word
    > latency.

    Teaching English is not my thing, but latent
    means "dormant", which means doing nothing. So
    the time it takes to perform a task is not
    latency. Its the time it really takes compared to
    the time it ought to take if there was no
    overhead. If you have a perfect implementation
    then you have no latency. Your definition implies
    that there is no way to have zero latency, which
    is just wrong.

    I've seen computer dictionaries that define
    latency as the time it takes to get a response.
    That would mean a network switch's latency is
    different with different sized packets, which is
    just plain stupid.

    None of this is helpful, but since no one has
    been able to tell me how to tune it to provide
    absolute priority to the network stack I'll
    assume it can't be done.

    DT

    __________________________________________________
    Do You Yahoo!?
    Tired of spam? Yahoo! Mail has the best spam protection around
    http://mail.yahoo.com
    -
    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: 2005-08-23 22:12    [W:0.044 / U:30.084 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site