Re: Iperf max b/w
I was recently doing some gigE testing ... 940 Mb/s was a
number I saw with 1500 byte MTU hosts; you may have to go
to 9000 byte MTUs to get 990.
Note that for all of these there must be no loss, with the
bottleneck being the host interface; if you ever get
into TCP's "sawtooth" pattern, the maximum you'll achieve
is ~75% of the raw bitrate and probably much less.
[FWIW, I've done this with a syskonnect gigE card & 64 bit
66 Mhz PCI bus machine; PCI-X should give you more headroom.]
--On Friday, October 10, 2003 9:50 AM -0500 Tony Rimovsky <tony --at-- ncsa.uiuc.edu> wrote:
> there could be several host bottlenecks:
> 1. pci bus speed.
> 2. other host activity.
> 3. frame size and io/cpu utilization
> 4. tcp implimentation problems
> --On Friday, October 10, 2003 8:36 AM -0600 Cameron Harr <charr --at-- lnxi.com> wrote:
>> Tony Rimovsky wrote:
>>> It may be a host limitation. We've seen iperf perform faster than that
>>> (990 Mbps) on high latency gigabit paths with larger windows.
>> Ok. For my aid, when you say host, are you thinking PCI-X bridge to Gig-E
>> nic (hardware)?
>> Cameron Harr
>> Systems Engineer
>> Linux Networx Inc