But you had a tail-wind. I take it that the bottom half can execute
more than 100x a second if the machine is otherwise idle. But if
anything comes along and uses a whole timeslice, the backlog queue
fills (default size 300) and you start dropping packets on the floor.
Yes? No?
And routing is fairly efficient; it's all in the kernel, at
least. Sniffing, on the other hand, consumes a fair bit of extra CPU
time getting the data up to the user process and consuming it.
> The fun with NFR isnt the device backlog, its that BSD has a hack built into
> it basically solely for sniffing tools to use, and Linux doesn't.
That may be the key to getting to *really* high packet rates. But Linux,
pin their test, slowed down as the packet rate increased. That's what
made me suspect the backlog. But it's just a guess.
-- g
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