Re: Why does windows2000 ping have a resolution of 10ms?

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#74

From: Will Dean
Date: Wed, 27 Mar 2002 19:18

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"Duncan" <duncan@little.demon.co.uk> wrote in message
news:9XOVUIAqzgo8Ewut@little.demon.co.uk...
>
> Anyone else getting 1ms?

The default system timer tick on NT/2K/XP machines is generally 10ms on
single-processor x86, and 15ms on multiprocessor machines.

However, it's open to any application on the system to speed this up to as
fast as 1ms, by making a specific API call.   Because there is of course
only one system timer, this change will affect all applications which are
running, quite possibly including ping.

I suspect that people are seeing a difference because of something
completely unrelated running on their system which has happened to speed up
the timer.

Changes in XP mean the the ping timing is not dependant on this clock,
instead it uses either the higher resolution of the counts _between_ the
timer tick - these are at roughly 800ns on single-processor machines, or the
processor clock, which is obviously _very_ high resolution nowadays.

If you can find something (of the VC variety) to compile it, the following
code might make a difference to your system:

#include <windows.h>
#include <mmsystem.h>
#pragma comment(lib, "winmm.lib")

int main()
{
    timeBeginPeriod(1);
    Sleep(INFINITE);
    return 0;
}

If you want me to compile if for you, email me separately.

Cheers,

Will

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From: "Will Dean" <abuse@industrial.demon.co.uk>
Newsgroups: demon.ip.support.nt,demon.service.isdn
Subject: Re: Why does windows2000 ping have a resolution of 10ms?
Date: Wed, 27 Mar 2002 19:18:36 -0000
Organization: Industrial Computing Ltd
Message-ID: <1017257768.16192.0.nnrp-14.9e98cb7d@news.demon.co.uk>
References: <EuZLqJATKJh8EwS3@little.demon.co.uk> <MPG.16efdfd3d98514899896d0@news-central.giganews.com> <tfob8u08b1ki0aj37odct94f5naflt5vt1@4ax.com> <1015457895.3495.1.nnrp-10.c2de3c6e@news.demon.co.uk> <goUi7KAqufi8Ewut@little.demon.co.uk> <MPG.16f53b8526cd31d99896d4@news-central.giganews.com> <9XOVUIAqzgo8Ewut@little.demon.co.uk>
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