Subba Rao wrote:
>
> Hello,
>
> I have 2 3Com NICs on my system. They are 3c905C Tornado PCI cards.
> The drivers are compiled into the kernel (Slackware 8.0 with kernel 2.4.7).
>
> One of the interfaces will be used as a sniffer interface (without IP address)
> and a very high traffic pipes. I do not wish to loose any packets coming to this
> interface. Is it better if I initialize the interface in HALF DUPLEX mode? If yes,
> how do I set the card to HALF DUPLEX mode? How can I find out the HW (NIC) settings
> on the system?
No, this will provide no benefit.
> Another question about 3Com NICs, do they perform zero-copy IP?
Linux's zerocopy infrastructure allows the sendfile() system call
to save a copy with NICs which have hardware checksumming and
scatter/gather. 3c905C is one such NIC. Kernel is not generally
"zero copy", but large savings are available in certain situations.
NFS packet reassembly benefits from 905C's as well.
> I read that the performance improves a lot WITHOUT zero-copy IP.
Not right. Where did you read that?
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This archive was generated by hypermail 2b29 : Wed Aug 15 2001 - 21:00:34 EST