On Mittwoch 11 April 2007, Tom Eastep wrote: > Since rebuilding my server, I have been fighting a traffic shaping problem. > The symptoms are: > > a) HTB classes consistently exceeded their specified ceilings. > b) HTB classes reported a large number of 'giants' in the output of > "shorewall show tc". > > Example (I acually saw this class reach the maximum uplink capacity at one > point): > > class htb 1:130 parent 1:1 leaf 130: prio 3 quantum 1500 rate 76000bit ceil > 230000bit burst 1537b/8 mpu 0b overhead 0b cburst 1614b/8 mpu 0b overhead > 0b level 0 > Sent 559018700 bytes 75324 pkt (dropped 0, overlimits 0 requeues 0) > rate 269288bit 3pps backlog 0b 0p requeues 0 > lended: 53963 borrowed: 21361 giants: 90174 > tokens: -26688 ctokens: -14783 > > I finally traced it to our old friend "checksum offloading". With the Xen 3 > package included with OpenSuSE 10.2, it is no longer necessary to run > ethtool to get communications to work. *But*, if you don't run "ethtool -K > eth0 tx off" in your domUs, traffic shaping in Dom0 *doesn't work*.
Not only traffic shaping, also connection tracking can fail. (Tom, you remember my FTP issue?) Also a *LOT* of TCP retransmission happens because of wrong checksums. So better switch the checksum offloading off, regardless of traffic shaping. Just my 2 cents, Alex ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Shorewall-users mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/shorewall-users
