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Date:      Wed, 16 Oct 2002 08:57:19 +0300
From:      "Petri Helenius" <pete@he.iki.fi>
To:        "Luigi Rizzo" <rizzo@icir.org>
Cc:        "Lars Eggert" <larse@ISI.EDU>, <freebsd-net@FreeBSD.ORG>
Subject:   Re: ENOBUFS
Message-ID:  <06c901c274d8$e5280b80$8c2a40c1@PHE>
References:  <065901c27495$56a94c40$8c2a40c1@PHE> <3DAC8FAD.30601@isi.edu> <068b01c2749f$32e7cf70$8c2a40c1@PHE> <20021015161055.A27443@carp.icir.org>

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>
> how large are the packets and how fast is the box ?

Packets go out at an average size of 1024 bytes. The box is dual
P4 Xeon 2400/400 so I think it should qualify as "fast" ? I disabled
hyperthreading to figure out if it was causing problems. I seem to
be able to send packets at a rate in the 900Mbps when just sending
them out with a process. If I do similar sending on two interfaces at
same time, it tops out at 600Mbps.

The information I´m looking for is how to instrument where the
bottleneck is to either tune the parameters or report a bug in PCI or
em code. (or just simply swap the GE hardware to something that
works better)

Pete


> on a fast box you should be able to generate packets faster than wire
> speed for sizes around 500bytes, meaning that you are going to saturate
> the queue no matter how large it is.
>
> cheers
> luigi
>
> > em-interface is running 66/64 and is there a way to see interface queue
depth?
> > em0: <Intel(R) PRO/1000 Network Connection, Version - 1.3.14> port
0x3040-0x307f
> > mem 0xfc220000-0xfc23ffff irq 17 at device 3.0 on pci2
> > em0:  Speed:1000 Mbps  Duplex:Full
> > pcib2: <PCI to PCI bridge (vendor=8086 device=1460)> at device 29.0 on pci1
> > IOAPIC #2 intpin 0 -> irq 16
> > IOAPIC #2 intpin 6 -> irq 17
> > IOAPIC #2 intpin 7 -> irq 18
> > pci2: <PCI bus> on pcib2
> >
> > The OS is 4.7-RELEASE.
> >
> > Pete
> >
> >
> >
> > To Unsubscribe: send mail to majordomo@FreeBSD.org
> > with "unsubscribe freebsd-net" in the body of the message
>



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