On Thu, 10 Jun 2004, Steven M. Bellovin wrote:

> You might want to install pkgsrc/ttcp; it's a standard way of doing
> exactly that sort of test.

Thanks, I'll try that.

> That said -- how are the two machines interconnected?  I've had similar
> network performance issues when the duplex setting on my NIC disagreed
> with the switch.  To be sure, it was a weird built-in 3Com NIC on a
> Dell machine where I had to disable auto-negotiate (I can dig up the PR
> number if you want), but the net effect was that if I set things
> incorrectly, I could do slow speed network I/O but not high speed.

They are physically connected almost directly, there is one switch
between them. The connection is 100baseTX-FDX.

However, at least according to my test, it seems that the network I/O
seems to be very good. Since if I get data from NIC only to the
memory buffer, everything goes very fast. Only when the disk is used
between network transmissions, things start to go slowly.

I have also observed this same problem using another NIC in the
i386 (rtk, the same I have in the alpha). This problem also
occurs on three different disks, and I've also tried another IDE card...
The only thing I've left is to switch the motherboard.