tech-net: Making ipintrq ifq_len and ifq_max readable and writable via sysctl

Subject: Making ipintrq ifq_len and ifq_max readable and writable via sysctl
To: None <tech-net@netbsd.org>
From: Jonathan Stone <jonathan@DSG.Stanford.EDU>
List: tech-net
Date: 08/15/2003 16:19:50

I've locally tweaked the bge driver to do heavy interrupt mitigation;
up to ~44 received packets per interrupt.  With two or three interfaces
running at that load, its ~trivial to overflow the ip input queue.

I propose to add sysctl knobs to allow examining and modifying the
current and max depth of inpintrq:

	  net.inet.ip.intr_queue_maxlen
	  net.inet.ip.intr_queue_drops
	  net.inet.ip.intr_queue_len

(intr_queue_len is new, the other two match the FreeBSD names.)  I've
had the code running on a couple of test systems for some time, I just
need to clean it up and remerge it again after fast-ipsec.

Any objections?