Date: Fri, 18 Oct 2002 10:59:22 -0700 From: Luigi Rizzo <rizzo@icir.org> To: Kelly Yancey <kbyanc@posi.net> Cc: Petri Helenius <pete@he.iki.fi>, Lars Eggert <larse@ISI.EDU>, freebsd-net@FreeBSD.ORG Subject: Re: ENOBUFS Message-ID: <20021018105922.E82982@carp.icir.org> In-Reply-To: <20021018103653.V1611-100000@gateway.posi.net>; from kbyanc@posi.net on Fri, Oct 18, 2002 at 10:45:13AM -0700 References: <20021018103319.A82982@carp.icir.org> <20021018103653.V1611-100000@gateway.posi.net>
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How is the measurement done, does the box under test act as a router
with the smartbit pushing traffic in and expecting it back ?
The numbers are strange, anyways.
A frame of N bytes takes (N*8+160) nanoseconds on the wire, which
for 330-byte frames should amount to 1000000/(330*8+160) ~= 357kpps,
not the 249 or so you are seeing. Looks as if the times were 40% off.
cheers
luigi
On Fri, Oct 18, 2002 at 10:45:13AM -0700, Kelly Yancey wrote:
...
> > can push out over 400kpps (64byte frames) on a 2.4GHz box.
> >
> > luigi
> >
>
> Using a SmartBit to push traffic across a 1.8Ghz P4; 82543 chipset card
> plugged into PCI-X bus:
>
> FrameSize TxFrames RxFrames LostFrames Lost (%)
> 330 249984 129518 120466 48.19
> 331 249144 127726 121418 48.73
> 332 248472 140817 107655 43.33
> 333 247800 247800 0 0
>
> It has no trouble handling frames 333 bytes or larger. But for any frame
> 332 bytes or smaller we consistently see ~50% packet loss. This same machine
> easily pushes ~100Mps with the very same frame sizes using a bge card rather
> than em.
>
> I've gotten the same results with both em driver version 1.3.14 and 1.3.15
> on both FreeBSD 4.5 and 4.7 (all 4 combinations, that is).
>
> Kelly
>
> --
> Kelly Yancey -- kbyanc@{posi.net,FreeBSD.org}
> FreeBSD, The Power To Serve: http://www.freebsd.org/
>
>
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