From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?B?T3J0d2luIEdsw7xjaw==?= Subject: Re: 3.14 regression: huge latency in read/select on tun Date: Fri, 04 Apr 2014 10:34:11 +0200 Message-ID: <533E6E83.7030106@odi.ch> References: <533C381E.9090103@odi.ch> <1396456973.3989.41.camel@edumazet-glaptop2.roam.corp.google.com> <533D133A.3090008@odi.ch> <1396531176.12330.6.camel@edumazet-glaptop2.roam.corp.google.com> <1396533026.12330.9.camel@edumazet-glaptop2.roam.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org To: Eric Dumazet Return-path: In-Reply-To: <1396533026.12330.9.camel@edumazet-glaptop2.roam.corp.google.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 03.04.2014 15:50, Eric Dumazet wrote: > If bug is in tun.c you have this list of changes you could bisect > from : > > # git log --oneline v3.13..v3.14 drivers/net/tun.c > 6671b2240c54 tun: remove bogus hardware vlan acceleration flags from vlan_features > 99932d4fc03a netdevice: add queue selection fallback handler for ndo_select_queue > 93e14b6d776e tun: add device name(iff) field to proc fdinfo entry > fa35864e0bb7 tuntap: Fix for a race in accessing numqueues > 0a379e21c503 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net > fbe4d4565bad tun, rfs: fix the incorrect hash value > 9bc8893937c8 tun: Add support for RFS on tun flows > 143c90549494 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net > 3958afa1b272 net: Change skb_get_rxhash to skb_get_hash > 42404c091510 Revert "tun: remove useless codes in tun_chr_aio_read() and tun_recvmsg()" > 73713357ab58 tun: remove useless codes in tun_chr_aio_read() and tun_recvmsg() > 34f9f437104b Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net > f96eb74c84eb tun: remove unused parameter in tun_do_read() > 92d4ea6e412a tun: spelling fixes That list doesn't look too promising. I'd rather look in net/ipv4 which does have TSO/GSO related changes. I tried to bisect that but the system hangs on boot when net devices are enabled. So it may prove difficult to pin down. I may try again during the weekend.