From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: [PATCH net-next] net_sched: add 64bit rate estimators Date: Wed, 5 Jun 2013 19:55:31 +0100 Message-ID: <1370458531.1918.3.camel@bwh-desktop.uk.level5networks.com> References: <1370408447.24311.241.camel@edumazet-glaptop> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: David Miller , netdev To: Eric Dumazet Return-path: Received: from webmail.solarflare.com ([12.187.104.25]:27868 "EHLO webmail.solarflare.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756662Ab3FESzk (ORCPT ); Wed, 5 Jun 2013 14:55:40 -0400 In-Reply-To: <1370408447.24311.241.camel@edumazet-glaptop> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, 2013-06-04 at 22:00 -0700, Eric Dumazet wrote: > From: Eric Dumazet > > struct gnet_stats_rate_est contains u32 fields, so the byte per second > field can wrap at 34360Mbit. > > Add a new gnet_stats_rate_est64 structure to get 64bit bps field, and > switch the kernel to use this structure natively. [...] > /** > + * struct gnet_stats_rate_est64 - rate estimator > + * @bps: current byte rate > + * @pps: current packet rate > + */ > +struct gnet_stats_rate_est64 { > + __u64 bps; > + __u32 pps; > +} __attribute__ ((packed)); [...] Using attribute packed (which should be written as __packed) forces the alignment of each member and the structure as a whole to be 1. For an architecture where unaligned access is expensive, gcc will make all reads and writes use byte operations. I think you have to add a dummy __u32 member instead. Ben. -- Ben Hutchings, Staff Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.