From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Graf Subject: Re: [PATCH net-next] sctp: support per-association stats via a new SCTP_GET_ASSOC_STATS call Date: Tue, 30 Oct 2012 14:51:56 +0000 Message-ID: <20121030145156.GN13450@casper.infradead.org> References: <1351258973-17227-1-git-send-email-michele@acksyn.org> <20121026143704.GC25087@hmsreliant.think-freely.org> <20121029084143.GA17442@casper.infradead.org> <20121029113700.GA9332@hmsreliant.think-freely.org> <508EE586.9060907@gmail.com> <20121030125230.GB13450@casper.infradead.org> <508FE34D.8010402@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Neil Horman , Michele Baldessari , linux-sctp@vger.kernel.org, "David S. Miller" , netdev@vger.kernel.org To: Vlad Yasevich Return-path: Received: from casper.infradead.org ([85.118.1.10]:56903 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754131Ab2J3OwB (ORCPT ); Tue, 30 Oct 2012 10:52:01 -0400 Content-Disposition: inline In-Reply-To: <508FE34D.8010402@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: On 10/30/12 at 10:25am, Vlad Yasevich wrote: > Can you give me some reasons why you prefer 0? > > 0 seems a bit strange to me. if someone was to construct a > histogram of values, they would start with some initial value, then > see 0s if there is no change, a spike for large rto, and if the > spike is corrected, it would drop to 0 indicating no change... > Seems odd. > > I would rather see what the current observed max rto is for an > application polling period. Then a histogram can be correctly > constructed. 0 would indicate that the rto has not been recalculated since the last read and the app can decideitself whether to ignore that read, replace it with rto_min or use the last known good rto_max value. Obviously this would mean that the patch needs to be changed so it updates the max observed rto after applying rto_min in sctp_transport_update_rto(). I'm perfectly fine with using rto_min as well though, we just lose a bit of information that may be helpful to some users.