The in-kernel and out-of-tree driver aren't exactly the same and there could be differences enforced by the community that create that difference. For example - and I'm just making this up - there could be a difference in the dropping or passing of packets with bad checksums.
More likely are differences in the default settings of the two drivers. You may want to check that first. If you have a clearly reproducible use case, we can try looking into this, but we are a bit limited in the number of Opteron systems we have in-house. Todd Fujinaka Software Application Engineer Networking Division (ND) Intel Corporation todd.fujin...@intel.com (503) 712-4565 -----Original Message----- From: Steffen Persvold [mailto:s...@numascale.com] Sent: Thursday, December 18, 2014 10:36 PM To: e1000-devel@lists.sourceforge.net Cc: Daniel J Blueman Subject: [E1000-devel] Sporadic packet loss observed with newer in-kernel drivers (5.2.15-k) Hi, We’re currently working with a cluster of SuperMicro H8QGL (http://www.supermicro.com/Aplus/motherboard/Opteron6000/SR56x0/H8QGL-iF.cfm) based systems which has two of the 82576 chips : 02:00.0 Ethernet controller: Intel Corporation 82576 Gigabit Network Connection (rev 01) 02:00.1 Ethernet controller: Intel Corporation 82576 Gigabit Network Connection (rev 01) Consequently the kernel use the igb network driver for this. We have observed with kernels 3.14 and onwards that we sometimes get packet-loss (due to corrupted packets). 3.14 uses igb version 5.0.5-k : [ 0.000000] Linux version 3.14.27-numascale27+ (sp@build-ubuntu) (gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1) ) #2 SMP Thu Dec 18 08:00:08 CET 2014 ... [ 6.338430] igb: Intel(R) Gigabit Ethernet Network Driver - version 5.0.5-k [ 6.345394] igb: Copyright (c) 2007-2013 Intel Corporation. If we revert back to 3.10 kernels (3.10.63), which uses the 5.0.3-k igb driver we have no packet loss scenarios : [ 0.000000] Linux version 3.10.63-numascale27+ (sp@build-ubuntu) (gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1) ) #1 SMP Wed Dec 17 15:56:25 CET 2014 ... [ 6.749783] igb: Intel(R) Gigabit Ethernet Network Driver - version 5.0.3-k [ 6.756740] igb: Copyright (c) 2007-2013 Intel Corporation. I have also tested the most recent kernel; 3.18.1 : [ 0.000000] Linux version 3.18.1-numascale27+ (sp@build-ubuntu) (gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1) ) #1 SMP Thu Dec 18 08:36:03 CET 2014 ... [ 8.010000] igb: Intel(R) Gigabit Ethernet Network Driver - version 5.2.15-k [ 8.010000] igb: Copyright (c) 2007-2014 Intel Corporation. Also in this version we observe packet loss/corrupted packets. While in the failed state we observe with ethtool -S (snapshot taken on 3.14 with igb-5.0.5-k) : rx_short_length_errors: 235 rx_errors: 235 rx_length_errors: 235 rx_queue_6_csum_err: 256 Now to the interesting part :) If I download igb-5.2.15.tar.gz from the sourceforge site (http://sourceforge.net/projects/e1000/files/igb%20stable/5.2.15/igb-5.2.15.tar.gz/download), and build this for 3.18.1, the packet loss is gone. Which doesn’t make sense at all since 3.18.1 already has 5.2.15 driver (albeit an in-kernel variant). This also applies if we apply the same driver version to the 3.14 kernel (replacing 5.0.5-k). Any idea what might be causing this ? Any insight you might have would be highly appreciated. Cheers, -- Steffen Persvold Chief Architect NumaChip, Numascale AS Tel: +47 23 16 71 88 Fax: +47 23 16 71 80 Skype: spersvold ------------------------------------------------------------------------------ Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration & more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=164703151&iu=/4140/ostg.clktrk _______________________________________________ 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 ------------------------------------------------------------------------------ Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration & more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=164703151&iu=/4140/ostg.clktrk _______________________________________________ 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
