From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Graf Subject: Re: [PATCH] Rate should be u64 to avoid integer overflow at high speeds (>= ~35Gbit) Date: Tue, 12 Mar 2013 15:42:45 +0000 Message-ID: <20130312154245.GA13101@casper.infradead.org> References: <1362885604-14006-1-git-send-email-j.vimal@gmail.com> <1362888229.4051.2.camel@edumazet-glaptop> <1362891937.4051.25.camel@edumazet-glaptop> <20130310004904.de508bfa.billfink@mindspring.com> <1362894876.4051.27.camel@edumazet-glaptop> <513F3BE1.2080409@genband.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Eric Dumazet , Bill Fink , Vimal , netdev@vger.kernel.org, shemminger To: Chris Friesen Return-path: Received: from casper.infradead.org ([85.118.1.10]:56830 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933065Ab3CLPmx (ORCPT ); Tue, 12 Mar 2013 11:42:53 -0400 Content-Disposition: inline In-Reply-To: <513F3BE1.2080409@genband.com> Sender: netdev-owner@vger.kernel.org List-ID: On 03/12/13 at 08:29am, Chris Friesen wrote: > The only problem I see is that you can't set the multiplier with a > new tool and then query the rate with old tools. > > But you're going to run into that problem with the old tools no > matter what you do--and not doing anything is a crappy option as > well. > > Some kind of multiplier or shift makes as much sense as anything > else. With old tools you get current behaviour, with new tools you > can specify a multiplying factor to trade off resolution vs > precision. The introduction of a shift operator or multiplier introduces inprecision. I'd much rather see new 64bit Netlink attributes that, if present, replace the old rate values and statistics. You will need to add a new Netlink attribute anyway and we might as well transfer the actual rate instead of a multiplier. Just like we did with IFLA_STATS64.