From owner-freebsd-net Mon Nov 27 13:40: 0 2000 Delivered-To: freebsd-net@freebsd.org Received: from alijku04.edvz.uni-linz.ac.at (alijku04.edvz.uni-linz.ac.at [140.78.182.1]) by hub.freebsd.org (Postfix) with ESMTP id 6DF0837B479 for ; Mon, 27 Nov 2000 13:39:55 -0800 (PST) Received: from sondermuell.oeh.uni-linz.ac.at (root@sondermuell.oeh.uni-linz.ac.at [140.78.214.105]) by alijku04.edvz.uni-linz.ac.at (8.8.8/8.8.8) with ESMTP id WAA83854 for ; Mon, 27 Nov 2000 22:39:53 +0100 Received: from atommuell.oeh.uni-linz.ac.at (root@atommuell.oeh.uni-linz.ac.at [140.78.214.101]) by sondermuell.oeh.uni-linz.ac.at (8.9.3/8.9.3) with ESMTP id WAA05993 for ; Mon, 27 Nov 2000 22:39:49 +0100 Received: from localhost (ferdl@localhost) by atommuell.oeh.uni-linz.ac.at (8.9.3/8.9.3) with ESMTP id WAA90788 for ; Mon, 27 Nov 2000 22:40:03 +0100 (CET) (envelope-from ferdl@atommuell.oeh.uni-linz.ac.at) Date: Mon, 27 Nov 2000 22:40:03 +0100 (CET) From: Ferdinand Goldmann To: freebsd-net@freebsd.org Subject: Strange lockups with Dummynet Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Hello. I am experiencing strange crashes on a machine which is being heavily used as a traffic shaper serving about 300 clients. The machine itsself is just an old Pentium machine, NICs are: tx0: port 0x6200-0x62ff mem 0xe1000000-0xe1000fff irq 11 at device 18.0 on pci0 miibus0: on tx0 nsphy0: on miibus0 nsphy0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto tx0: address 00:e0:29:39:bb:ab, type SMC9432BTX xl0: <3Com 3c905C-TX Fast Etherlink XL> port 0x6300-0x637f mem 0xe1001000-0xe100107f irq 9 at device 19.0 on pci0 xl0: Ethernet address: 00:50:da:0d:a8:a7 miibus1: on xl0 xlphy0: <3c905C 10/100 internal PHY> on miibus1 xlphy0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto Occasionally, I see these in the logs: (I hear this is due to hardware being too slow to respond to feed the NIC, which could be possible (P166)) xl0: transmission error: 90 xl0: tx underrun, increasing tx start threshold to 120 bytes I have set the following kernel parameters: maxusers 96 options NMBCLUSTERS=4096 I beefed up NMBCLUSTERS because FreeBSD ran out of them with the default setting. Currently: # netstat -m 637/1472/16384 mbufs in use (current/peak/max): 187 mbufs allocated to data 450 mbufs allocated to packet headers 186/934/4096 mbuf clusters in use (current/peak/max) 2236 Kbytes allocated to network (23% in use) I have configured between 3 and 4 pipes on this machine and declared a small ruleset which should shape the traffic according to my expectations. Today, I experienced the following: Upon adding a new pipe definition, the machine locked maybe an eyeblink after the command was set off. I.e., the machine was not ping'able anymore, and the console was dead. However, the activity LEDs of the NICs were still flashing. No kernel entries, nothing... This has happened already once after rising the NMBCLUSTERS value. Being paranoid, I have been logging this value to a file, but it does not seem to rise significantly before the crash. [Q]: Can the change of NMBCLUSTERS be the cause for my lockup problem, or could this be a dummynet problem? How do people running sites with lots of traffic setting the values of maxusers and NMBCLUSTERS to be safe, and what would be the maximum value for maxusers (I heard long it is instable > 128)? General question, how stable is dummynet under heavy load, any experiences there? BTW, the machine is also doing port forwarding of HTTP connects to a proxy. TIA for any hints, Ferdinand Goldmann To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message