From mboxrd@z Thu Jan 1 00:00:00 1970 From: Denys Fedoryshchenko Subject: Re: loaded router, excessive getnstimeofday in oprofile Date: Wed, 27 Aug 2008 15:09:17 +0300 Message-ID: <200808271509.18529.denys@visp.net.lb> References: <200808220457.40892.denys@visp.net.lb> <48B46B48.7030609@cosmosbay.com> <20080826205158.GA15266@2ka.mipt.ru> Mime-Version: 1.0 Content-Type: Multipart/Mixed; boundary="Boundary-00=_uPUtIK8vFW3CqnH" Cc: Eric Dumazet , netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Evgeniy Polyakov Return-path: Received: from relay2.globalproof.net ([194.146.153.25]:56466 "EHLO relay2.globalproof.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754565AbYH0MKt (ORCPT ); Wed, 27 Aug 2008 08:10:49 -0400 In-Reply-To: <20080826205158.GA15266@2ka.mipt.ru> Sender: netdev-owner@vger.kernel.org List-ID: --Boundary-00=_uPUtIK8vFW3CqnH Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline On Tuesday 26 August 2008, Evgeniy Polyakov wrote: > On Tue, Aug 26, 2008 at 10:44:56PM +0200, Eric Dumazet (dada1@cosmosbay.com) wrote: > > >Do you have any packet sockets in this system? Like running dhcp daemon? No, nothing at all. > > > > Another way to see this problem can be to start a sniffer on the machine, > > even with a restrictive pcap filter, to check if performance change or > > not. (It should decrease) Yes, when i run tcpdump even without promisc at peak time, machine will be almost dead. Transit traffic will be 100ms+. I know that it is timestamping packets. Same almost for any libpcap app. > > Or just check /proc/net/packet iirc. > Anyway, having at least one packet socket ends up with timestamping of > each packet, so you will get fair load of getnstimeofday() in that case. There is very short list of tasks. Attached. /proc/net/packet clean, nothing there. > > > For example, I believe that running "ping" could have the same effect > > (increasing netstamp_needed variable : every incoming packet has to be > > timestamped) Even answering icmp timestamp request will take resources. > > > > So beware of pings, traceroute and other networking tools... When i am measuring performance - they are all off. > > Yup, this innocent toys can end up with this such behaviour on modern > highly loaded machines. --Boundary-00=_uPUtIK8vFW3CqnH Content-Type: text/plain; charset="iso-8859-1"; name="tasks.txt" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="tasks.txt" tcp 0 0 127.0.0.1:2600 0.0.0.0:* LISTEN 3167/zebra tcp 0 0 0.0.0.0:2601 0.0.0.0:* LISTEN 3167/zebra tcp 0 0 0.0.0.0:2602 0.0.0.0:* LISTEN 3174/ripd tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 3549/sshd tcp 0 0 194.146.153.17:22 194.146.154.161:37549 ESTABLISHED11593/sshd tcp 0 0 194.146.153.17:22 192.168.0.92:45891 ESTABLISHED11803/sshd tcp 0 0 127.0.0.1:42537 127.0.0.1:2600 ESTABLISHED3174/ripd tcp 0 0 194.146.153.17:22 194.146.153.18:51810 ESTABLISHED11799/sshd tcp 0 0 127.0.0.1:2600 127.0.0.1:42537 ESTABLISHED3167/zebra udp 0 0 0.0.0.0:520 0.0.0.0:* 3174/ripd udp 0 0 0.0.0.0:161 0.0.0.0:* 3194/snmpd udp 0 0 0.0.0.0:67 0.0.0.0:* 3207/udhcpd udp 111360 0 0.0.0.0:49619 0.0.0.0:* 2449/syslogd --Boundary-00=_uPUtIK8vFW3CqnH--