[rhn-users] Gigabit transfer speeds

Tue Aug 22 15:10:02 UTC 2006

The testing also involved linux/windows communications...

>From the webpage:
"Note: All cards were tested at 1500, 3000, 4000, and 6000 values for the
TCP MTU size. The drivers for the cards were not modified. Cards based upon
the dp83820 chipset were limited to 6000MTU due to driver defaults. All
other cards were tested through 9000MTU."

NOTE: http://www.cs.uni.edu/~gray/gig-over-copper/gig-over-copper.htmldescribes
that the benchmarks were gathered using Netpipe
2.4:
http://www.scl.ameslab.gov/netpipe

>From the above netpipe webpage ... "Gigabit Ethernet delivers around 900
Mbps with latencies of 25-62 microseconds from 64-bit 66 MHz PCI buses."

 .. I haven't substantiated this but you may wish to consider the 100K+
packet size as the TcpWindowSize as described in

http://support.microsoft.com/kb/314053/en-us

" Description: This parameter determines the maximum TCP receive window size
of the computer. The receive window specifies the number of bytes a sender
can transmit without receiving an acknowledgment. Generally, larger receive
windows improve performance over high (delay * bandwidth) networks. For
highest efficiency, the receive window must be an even multiple of the TCP
Maximum Segment Size (MSS)."

The complete benchmark write-up is located at:

http://www.cns.uni.edu/~gray/gig-over-copper/hsln-lcn.ps<http://www.cns.uni.edu/%7Egray/gig-over-copper/hsln-lcn.ps>

These were the OS environments:( Note: Even the win2k tests were over
600mbs....)

"Each system was configured to boot
into Debian 3.0 GNU/Linux and Microsoft Windows 2000
Professional. Versions 2.4.7, 2.4.19-pre9-ac2, and 2.5.7 of
the Linux kernel were used for testing on the GNU/Linux
operating system. Service pack 2 was applied to the Win-
dows 2000 installation."

Tim

On 8/21/06, Dan Hunter <dmhunter at charter.net> wrote:
>
>  I have already set the packet size as large as the windows driver allow -
> MTU = 7 Kb
>
> But coping from a very high speed disk, or RAM drive is certainly a good
> question.
> Is the limitation the ethernet, PCI bus, hard driver controller, or the
> hard drive itself????
>
> Hmmm, me thinks an experiment or two is in the wind!
>
> ----- Original Message -----
> *From:* Tim Schoenfelder <tim at timschoenfelder.com>
> *To:* Red Hat Network Users List <rhn-users at redhat.com>
> *Sent:* Monday, August 21, 2006 1:37 PM
> *Subject:* Re: [rhn-users] Gigabit transfer speeds
>
> Increase your packet size...
>
> One of our networking class projects a couple years ago was to benchmark
> gigibit ethernet transfer speeds.
>
> I benchmarked 700mb/s+ between two Linux PCs which was reasonable to our
> instructor.
>
> He emphasized that the brand/chipset of cards made a big difference ( it
> wasn't the most expensive that performed best ... ) as well as the drivers.
>
> Some of his published tests as described below show that you can achieve
> at least 700mb/s even with 32bit Netgear GA622T cards as illustrated in a ps
> link from his website:
>
> http://www.cs.uni.edu/~gray/ <http://www.cs.uni.edu/%7Egray/>
>
> Benchmark project links:
> http://www.cs.uni.edu/~gray/gig-over-copper/<http://www.cs.uni.edu/%7Egray/gig-over-copper/>
> http://www.cs.uni.edu/~gray/gig-over-copper/gig-over-copper.html<http://www.cs.uni.edu/%7Egray/gig-over-copper/gig-over-copper.html>
>
> PS file showing performance benchmarks ( note 700mb/s+ requires packet
> size of 100k+ bytes ):
>
> http://www.cs.uni.edu/~gray/gig-over-copper/hsln-lcn.ps<http://www.cs.uni.edu/%7Egray/gig-over-copper/hsln-lcn.ps>
>
> Tim
>
> On 8/21/06, Corne Beerse <cbeerse at gmail.com> wrote:
> >
> > Dan Hunter wrote:
> >
> > > I regularly move large files from a windows XP machine to a Fedora
> > > Core 5 machine.
> > > To avoid bothering other network users, I purchased two Linksys EG1032
> > > gigabit ether net cards.
> > > The cards have been installed.  a direct PC to PC gigabit cross over
> > > cable connects them.
> > > A separate set of IP address have been set up.
> > > I can verify that data is being transfered over the gigabit cable with
> >
> > > windows task manager.
> > >
> > > Transfers over the 10/100 link show up at 82 or 83 percent - about 80
> > > Mbps.
> > > Transfers over the gigabit link show up at 20 to 26 percent - about
> > > 230 Mbps.
> > >
> > > What do I have set up wrong?
> > >
> > >
> > Your expectations are to high. If you have about 20% utilisation with a
> > Gbit nic, I'd say you are doing verry nice.
> >
> > With the move to gigabit networking, the nic is no longer the
> > bottleneck. If you move data from disk on one machine or to disk on an
> > other, the disk-controllers, disk interfaces or even the actual disks
> > are most likely the bottlenecks. Then, the disk does not need to be the
> > bottleneck. Think about the speed of internal busses and for which they
> > are used while you are dumping data...
> >
> >
> > CBee
> >
> > _______________________________________________
> > rhn-users mailing list
> > rhn-users at redhat.com
> > https://www.redhat.com/mailman/listinfo/rhn-users
> >
>
>
>
> --
> Tim Schoenfelder
> http://timschoenfelder.com
>
> ------------------------------
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-- 
Tim Schoenfelder
http://timschoenfelder.com
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