Hello, first of all, sorry for mailing directly to dev. list. Hopefully it won't be inappropriate.
I came to weird performance and bandwidth issues with several new Supermicro server models with X722 NICs and Centos 7. Achievable bandwidth for client to server TCP connections was always roughly half of bandwidth for the other direction.. something like 450 Mbps upstream vs. 900 Mbps downstream at standard gig. network. Tested with iperf, but naturally affected also all "real" services there. But only under certain conditions. - Windows 10/Server 2016 clients, I tried also Windows 7, Linux, OS X, but those wasn't affected - i40e module on Centos 7 (kernels between 3.10.0-957.el7 and latest 3.10.0-1062.1.2.el7), it doesn't happen at Centos 8 nor Clonezilla live distro with 5.x kernel from Debian Sid. - it happens with both built-in i40e driver 2.8.10 and the latest released source here - 2.10.19.30, other NICs with different drivers (like igb) at the same server are fine It took me a while to isolate that and find some workaround (and resist crazy ideas, like migrate, recompile and qualify every custom package to Centos 8 in days, go and get few Broadcom NICs ;)). The workaround, which helped, is to disable ntuple Rx filters with ethtool and enable them again. I don't use any filtering there and even before that forced flushing, ethtool -n correctly reports zero rules there, there aren't any reported Rx dropped packets etc. After that flushing applied, Rx performance is back at expected values. I've attached text file with iperf figures and some further info about one of used servers. I'm not currently sure, whether it can qualify as a bug for entry to tracker. Maybe someone else could find the workaround useful, if he will be looking for a remedy. Anyway it was for first time, when I experienced such issue only with particular clients (Win 10), it was quite puzzling. Do you know, what can be different in TCP communication there and can trigger such issue and interaction, compared to other systems? All the best, Michal _______________________________________________ E1000-devel mailing list E1000-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/e1000-devel To learn more about Intel® Ethernet, visit http://communities.intel.com/community/wired
