From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [net-next-2.6 PATCH] net: fast consecutive name allocation Date: Thu, 12 Nov 2009 22:26:08 -0800 Message-ID: <20091112222608.79d90e9e@nehalam> References: <200911130701.14847.opurdila@ixiacom.com> <200911130720.19671.opurdila@ixiacom.com> <4AFCF8D3.6090905@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Octavian Purdila , netdev@vger.kernel.org To: Eric Dumazet Return-path: Received: from mail.vyatta.com ([76.74.103.46]:40034 "EHLO mail.vyatta.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752838AbZKMG0T convert rfc822-to-8bit (ORCPT ); Fri, 13 Nov 2009 01:26:19 -0500 In-Reply-To: <4AFCF8D3.6090905@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, 13 Nov 2009 07:12:35 +0100 Eric Dumazet wrote: > Octavian Purdila a =C3=A9crit : > > On Friday 13 November 2009 07:01:14 you wrote: > >> This patch speeds up the network device name allocation for the ca= se > >> where a significant number of devices of the same type are created > >> consecutively. > >> > >> Tests performed on a PPC750 @ 800Mhz machine with per device sysct= l > >> and sysfs entries disabled: > >> > >> Without the patch With the patch > >> > >> real 0m 43.43s real 0m 0.49s > >> user 0m 0.00s user 0m 0.00s > >> sys 0m 43.43s sys 0m 0.48s > >> > >=20 No one has give a reasonable use case for this network device name explosion, what is the benchmark doing this nosense, and how do I get paid to do it... But I have to say no for another reason. You cause the kernel to choose a different name for the case where a device is deleted or renamed. The old code would find and fill the hole when a new device was added. Since this is a semantic ABI change, the kind that drives users nuts. --=20