From mboxrd@z Thu Jan 1 00:00:00 1970 From: alekcejk@googlemail.com Subject: limited network bandwidth with 3.2.x kernels Date: Mon, 13 Feb 2012 22:04:52 +0200 Message-ID: <8633039.fHPLx6GNq3@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit To: netdev@vger.kernel.org Return-path: Received: from mail-bk0-f46.google.com ([209.85.214.46]:44792 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757860Ab2BMUFH (ORCPT ); Mon, 13 Feb 2012 15:05:07 -0500 Received: by bkcjm19 with SMTP id jm19so4865560bkc.19 for ; Mon, 13 Feb 2012 12:05:05 -0800 (PST) Sender: netdev-owner@vger.kernel.org List-ID: Hi, I noticed that with 3.2.x kernels download speed from some internet resources became about half of speed that was with previous kernels (3.1 and older). I tested Fedora 15 kernels 2.6.41.10 = 3.1.10 and 2.6.42.3 = 3.2.3 (many times rebooted for testing with first and second kernels). See bug https://bugzilla.redhat.com/show_bug.cgi?id=789659 lsmod: Module Size Used by nvidia 10778232 40 i2c_core 28123 1 nvidia 8139too 32490 0 mii 13311 1 8139too dmesg: 8139too: 8139too Fast Ethernet driver 0.9.28 8139too 0000:01:02.0: PCI INT A -> GSI 22 (level, low) -> IRQ 22 8139too 0000:01:02.0: eth0: RealTek RTL8139 at , IRQ 22 8139too 0000:01:02.0: eth0: link up, 100Mbps, full-duplex, lpa 0x41E1 For testing I selected fastest for me download mirrors of FreeBSD and Ubuntu, also I tested download speed from site speedtest.tele2.net. For these sites download speed with 3.1 kernels (and older) is about 11 MB/s but with 3.2.x kernels - limited 5.5 MB/s and for some sites still approximately the same as with 3.1 kernels (see bug mentioned above). Also I want to pay attention that limited speed stays constant - always 5.5 MB/s with straight line on traffic plotter as if was network bandwidth shaping. With 3.1 kernels this never happens - speed can vary in some ranges but at maximum it is about 11 MB/s, no limitations such as 5.5 MB/s. -- Alexey Kurov