From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: regression: unregister_netdev() unusably slow Date: Sun, 24 May 2009 23:42:17 +0200 Message-ID: <4A19BF39.4000305@cosmosbay.com> References: <20090524192150.GE24757@kvack.org> <200905250023.31056.denys@visp.net.lb> <20090524213744.GG24757@kvack.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Denys Fedoryschenko , netdev@vger.kernel.org To: Benjamin LaHaise Return-path: Received: from gw1.cosmosbay.com ([212.99.114.194]:40412 "EHLO gw1.cosmosbay.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751720AbZEXVma convert rfc822-to-8bit (ORCPT ); Sun, 24 May 2009 17:42:30 -0400 In-Reply-To: <20090524213744.GG24757@kvack.org> Sender: netdev-owner@vger.kernel.org List-ID: Benjamin LaHaise a =E9crit : > On Mon, May 25, 2009 at 12:23:30AM +0300, Denys Fedoryschenko wrote: >> Once oprofile gave me hint about similar issue >=20 > I forgot to mention: there is no more than ~1% CPU usage while the in= terfaces=20 > are being deleted. I'm about half way through the bisect now and sho= uld have=20 > the culprit soon.=20 >=20 > -ben unregister a vlan here cost about 100 ms if CONFIG_NO_HZ is set, 50 ms = if not set (But vlan case might be litle bit more expensive than your case, since = we call synchronize_net() three times (once in unregister_vlan_dev(), and twice= in rollback_registered()