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: Fri, 13 Nov 2009 16:04:45 -0800 Message-ID: <20091113160445.7a3538ef@nehalam> References: <200911130701.14847.opurdila@ixiacom.com> <200911130720.19671.opurdila@ixiacom.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: Octavian Purdila Return-path: Received: from mail.vyatta.com ([76.74.103.46]:58926 "EHLO mail.vyatta.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754079AbZKNAFB (ORCPT ); Fri, 13 Nov 2009 19:05:01 -0500 In-Reply-To: <200911130720.19671.opurdila@ixiacom.com> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, 13 Nov 2009 07:20:19 +0200 Octavian Purdila wrote: > On Friday 13 November 2009 07:01:14 you wrote: > > This patch speeds up the network device name allocation for the case > > where a significant number of devices of the same type are created > > consecutively. > > > > Tests performed on a PPC750 @ 800Mhz machine with per device sysctl > > 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 Since the main overhead here is building the bitmap table used in the name scan. Why not mantain the bitmap table between calls by implementing a rbtree with prefix -> bitmap. The tree would have to be limited and per namespace but then you could handle the general case of adding a device, then its vlans, then another device, ... --