From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: [BUG] ixgbe: something wrong with queue selection ? Date: Tue, 17 Apr 2012 11:06:48 +0200 Message-ID: <1334653608.6226.11.camel@edumazet-laptop> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: netdev To: "Kirsher, Jeffrey T" , Greg Rose , John Fastabend , Jesse Brandeburg Return-path: Received: from mail-bk0-f46.google.com ([209.85.214.46]:55666 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755484Ab2DQJHD (ORCPT ); Tue, 17 Apr 2012 05:07:03 -0400 Received: by bkcik5 with SMTP id ik5so4333667bkc.19 for ; Tue, 17 Apr 2012 02:07:01 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: Hi guys I have bad feelings with ixgbe and its multiqueue selection. On a quad core machine (Q6600), I get lots of reorderings on a single TCP stream. Apparently packets happily spread on all available queues, instead of a single one. This defeats GRO at receiver and TCP performance is really bad. # ethtool -S eth5|egrep "x_queue_[0123]_packets" ; taskset 1 netperf -H 192.168.99.1 ; ethtool -S eth5|egrep "x_queue_[0123]_packets" tx_queue_0_packets: 24 tx_queue_1_packets: 26 tx_queue_2_packets: 32 tx_queue_3_packets: 16 rx_queue_0_packets: 11 rx_queue_1_packets: 47 rx_queue_2_packets: 27 rx_queue_3_packets: 22 MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.99.1 (192.168.99.1) port 0 AF_INET Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 3866.43 tx_queue_0_packets: 1653201 tx_queue_1_packets: 608000 tx_queue_2_packets: 541382 tx_queue_3_packets: 536543 rx_queue_0_packets: 434703 rx_queue_1_packets: 137444 rx_queue_2_packets: 131023 rx_queue_3_packets: 128407 # ip ro get 192.168.99.1 192.168.99.1 dev eth5 src 192.168.99.2 cache ipid 0x438b rtt 4ms rttvar 4ms cwnd 57 reordering 127 # lspci -v -s 02:00.0 02:00.0 Ethernet controller: Intel Corporation 82599EB 10-Gigabit SFI/SFP+ Network Connection (rev 01) Subsystem: Intel Corporation Ethernet Server Adapter X520-2 Flags: bus master, fast devsel, latency 0, IRQ 16 Memory at f1100000 (64-bit, prefetchable) [size=512K] I/O ports at b000 [size=32] Memory at f1200000 (64-bit, prefetchable) [size=16K] Capabilities: [40] Power Management version 3 Capabilities: [50] MSI: Enable- Count=1/1 Maskable+ 64bit+ Capabilities: [70] MSI-X: Enable+ Count=64 Masked- Capabilities: [a0] Express Endpoint, MSI 00 Capabilities: [100] Advanced Error Reporting Capabilities: [140] Device Serial Number 00-1b-21-ff-ff-4a-fe-54 Capabilities: [150] Alternative Routing-ID Interpretation (ARI) Capabilities: [160] Single Root I/O Virtualization (SR-IOV) Kernel driver in use: ixgbe Kernel modules: ixgbe