From owner-freebsd-hackers Thu Mar 25 19:18:14 1999 Delivered-To: freebsd-hackers@freebsd.org Received: from implode.root.com (root.com [209.102.106.178]) by hub.freebsd.org (Postfix) with ESMTP id 14F93151E7 for ; Thu, 25 Mar 1999 19:18:12 -0800 (PST) (envelope-from root@implode.root.com) Received: from implode.root.com (localhost [127.0.0.1]) by implode.root.com (8.8.8/8.8.5) with ESMTP id TAA00298; Thu, 25 Mar 1999 19:15:36 -0800 (PST) Message-Id: <199903260315.TAA00298@implode.root.com> To: Jonathan Lemon Cc: dillon@apollo.backplane.com, freebsd-hackers@FreeBSD.ORG Subject: Re: 3.1-STABLE dies on 40+ connects In-reply-to: Your message of "Thu, 25 Mar 1999 21:08:10 CST." <19990325210810.58396@right.PCS> From: David Greenman Reply-To: dg@root.com Date: Thu, 25 Mar 1999 19:15:36 -0800 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG >So that would explain why I see the peak value for NMBCLUSTERS >exceeding the max; the system allocated more, and then ran out of >space in the vm map. It's the total space in the "mb_map" that determines the real limit. The "max" in the netstat output is just the nmbclusters part, but the real max is the size of the map (which, again, also has space for mbufs). >But what I was really asking was at what point does the system decide >to put data in a cluster as opposed to putting it into a normal mbuf >and then tacking it onto the mbuf chain? As I understand it, the NIC >DMA's data directly into mbufs on it's receive ring; are these then >passed to ether_input. Are the buffers that the NIC uses always clusters? In general, the system uses mbuf clusters (large buffers) whenever there is more data than will fit into just a single mbuf. Device drivers have various policies, however, so what actually happens can vary. -DG David Greenman Co-founder/Principal Architect, The FreeBSD Project To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message