Advice on a multithreaded netisr patch?

Robert Watson rwatson at
Sun Apr 5 06:24:02 PDT 2009

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.

Robert N M Watson
Computer Laboratory
University of Cambridge

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