Re: Some questions about Iperf
> What kind of I/O subsystem do I need to have to sustain 200Mbit/s of data?
>
> The 32bit/33Mhz PCI bus can handle 132MB/s in theory.
>
> Let's say I lose 20% of that to protocol overhead (I'm generalizing, I know
> its not that great)
PCI/TCP/BLAH protocol overhead is not the only factor.
> That still leaves me with 105MB/s of bus throughput.
>
> One 10/100 onboard NIC running at 200Mbit/s is only needed 25MB/s of that
> bus throughput.
>
> So how is my I/O subsystem substandard here? I mean, the onboard NIC's are
> Intel chips, and I can't say that I've ever run into any kind of serious
> problems with them before.
Man I am just saying that there are other issues at stake here. Have you
pushed 200Mb through these Intel chips before? or across _your_ PCI bus?
Rattling off specifications is meaningless, ever tried to transfer 100MB/s
to a ATA100 drive? it just aint gonna happen!
> Has anyone else on here tried this particular kind of test setup before?
> I'm wide open to suggestions.
Actually I did run some tests that were bidirectional like yours, but I
did not connect them with a crossover cable, I left them how they were
currently connected to the network. I saw no degradation in performance
between the single direction and the simulataneous bidirection like you
are seeing. However these systems were both server class SMP machines that
have plenty of room to flex.
Kevin