Advice on a multithreaded netisr patch?

Ivan Voras ivoras at
Sun Apr 5 06:35:11 PDT 2009

Robert Watson wrote:
> On Sun, 5 Apr 2009, Ivan Voras wrote:
>> I thought this has something to deal with NIC moderation (em) but
>> can't really explain it. The bad performance part (not the jump) is
>> also visible over the loopback interface.
> FYI, if you want high performance, you really want a card supporting
> multiple input queues -- igb, cxgb, mxge, etc.  if_em-only cards are
> fundamentally less scalable in an SMP environment because they require
> input or output to occur only from one CPU at a time.

Makes sense, but on the other hand - I see people are routing at least
250,000 packets per seconds per direction with these cards, so they
probably aren't the bottleneck (pro/1000 pt on pci-e).

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 258 bytes
Desc: OpenPGP digital signature
Url :

More information about the freebsd-net mailing list