Min Miles Xu wrote:
Hi Roamer,
Yunsong (Roamer) Lu wrote:
I plan to fix this together with supporting LSO on VNICs, since there
are some relevant work to do together.
Yes, the CR 6762622 is really confusing. The original file CR was
tracking a performance issue, but finally the submitter changed the
synopsis to the current one to track the snoop display problem for
LSO packets. I'll update the CR shortly. Sorry for the confusions.
The simplest way to fix the CR is let snoop to check the LSO
information with the packet and avoid warning it. But I'm not sure
it's enough. Since LSO packets will be segmented by the NIC hardware
so on the wire there are only MTU-size packets. Are there suers who
expect to have a option for snoop to see the "expected packets on the
wire"? For example, `snoop -?` to parse the LSO packet header to
multiple regular headers that are expected to be seen on the wire?
I think snoop should only report what it really sees. For physical
devices, on the tx side, snoop can never see post-segmentation packets
on the wire. I don't think snoop should make a guess and report what
it has imagined to the users.
Correct.
All that an application can do is make educated guesses about what the
NIC will do, on the sending side, unless the NIC itself loops the packets
it sends back up. The idea behind snoop is to provide accurate reporting
on packet activity, not to make (educated) guesses.
It gets a little bit complex when we implement LSO on top of VNICs,
as is still being discussed. When snooping a VNIC created on e1000g,
should the snoops be seeing original LSO packets as sent to e1000g or
post-segmentation packets as seen on the wire? Any thoughts?
If "snoop -d vnic0", I think it should report original LSO packets. If
the real traffic passes through e1000g, "snoop -d e1000g0" should
report the real packets that are passed to e1000g (if e1000g LSO is
disabled, it should show regular Ethernet frames to users).
Again, I agree.
If LSO is causing problems for someone using snoop then ideally they should
be able to turn off LSO.
Darren
_______________________________________________
networking-discuss mailing list
[email protected]
