Subject: Re: packet capturing
To: Daniel Carosone <>
From: Jonathan Stone <>
List: tech-kern
Date: 01/21/2004 13:02:51
In message <>Daniel Carosone writes

>> And does NetBSD, by default, ship with polling drivers or irq based ?

Ask Jason.  I know FreeBSD's em driver does; I have packet traces of
the Intel-supplied FreeBSD em driver in FreeBSD 4.x slurping in a
64k-byte SMB packet train with one (1) interrupt at the end of the train.

(Not only were bpf's packet-arrival timestamps are closer than
physically possible for multiple interrupts; we instrumented calls
into the Rx handler to confirm it).

I have private patches which do an even more thorough job for the bge
driver: dynamically tuning for low latency or high througput.  they
require additional machinery to measure CPU load and turn the knob
accordingly, which NetBSD doesn't have.  (The specific driver settings
were calibrated by experiment with a bcm5700, and may need
recalibration for a commodity third-party bge device.)

I will look into releasing some portion of that code.