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Subject: Re: TCP/IP Speed
From: Terje Eggestad <terje.eggestad@scali.com>
To: root@chaos.analogic.com
Cc: Linux kernel <linux-kernel@vger.kernel.org>
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Date: 31 Jan 2002 15:00:27 +0100
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Hmmm, 

I tend to use the rdtsc register to do these kind of measurements, 
but I get ~110 uS round trip with or without TCP_NDELAY

I get ~100uS wehen pinging with raw ethernet frames.

PS: Intel 82557 Ethernet Pro 100 NIC's

TJ

ons, 2002-01-30 kl. 17:47 skrev Richard B. Johnson:
> On Wed, 30 Jan 2002, Zwane Mwaikambo wrote:
> 
> > On Wed, 30 Jan 2002, Richard B. Johnson wrote:
> > 
> > > But it's already connected.
> > > 
> > > 
> > >          host:
> > >          for (;;) {
> > >             gettimeofday(...);
> > >             write(s, buf, 64);
> > >             read(s, buf, sizeof(buffer));
> > >             gettimeofday(...);
> > >          /* delay is 1.0 ms */
> > >          }
> > >          server is IPPORT_ECHO
> > 
> > You didn't make that explicit in your previous email, and anyway what kind 
> > of resolution can you expect from gettimeofday...
> > 
> 
> The resolution is in microseconds. That's the specification. Not
> all 'codes' are exercised of course, but the resolution is sufficient
> to discern a 10 to 30 microsecond difference. I'm trying to measure
> milliseconds, well within its capability. FYI, this is what `ping`
> and `traceroute` use. It's fine.
> 
> 
> Cheers,
> Dick Johnson
> 
> Penguin : Linux version 2.4.1 on an i686 machine (797.90 BogoMips).
> 
>     I was going to compile a list of innovations that could be
>     attributed to Microsoft. Once I realized that Ctrl-Alt-Del
>     was handled in the BIOS, I found that there aren't any.
> 
> 
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-- 
_________________________________________________________________________

Terje Eggestad                  mailto:terje.eggestad@scali.no
Scali Scalable Linux Systems    http://www.scali.com

Olaf Helsets Vei 6              tel:    +47 22 62 89 61 (OFFICE)
P.O.Box 150, Oppsal                     +47 975 31 574  (MOBILE)
N-0619 Oslo                     fax:    +47 22 62 89 51
NORWAY            
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