From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from nm4-vm0.access.bullet.mail.sp2.yahoo.com (nm4-vm0.access.bullet.mail.sp2.yahoo.com [98.139.44.110]) by huchra.bufferbloat.net (Postfix) with SMTP id EEE7F200296 for ; Mon, 9 Jan 2012 14:13:32 -0800 (PST) Received: from [98.139.44.100] by nm4.access.bullet.mail.sp2.yahoo.com with NNFMP; 09 Jan 2012 22:13:30 -0000 Received: from [98.139.44.81] by tm5.access.bullet.mail.sp2.yahoo.com with NNFMP; 09 Jan 2012 22:13:30 -0000 Received: from [127.0.0.1] by omp1018.access.mail.sp2.yahoo.com with NNFMP; 09 Jan 2012 22:13:30 -0000 X-Yahoo-Newman-Id: 699731.79664.bm@omp1018.access.mail.sp2.yahoo.com Received: (qmail 94154 invoked from network); 9 Jan 2012 22:13:30 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=rogers.com; h=DKIM-Signature:X-Yahoo-Newman-Property:X-YMail-OSG:X-Yahoo-SMTP:Received:Message-ID:Date:From:Reply-To:User-Agent:MIME-Version:To:Subject:References:In-Reply-To:X-Enigmail-Version:Content-Type:Content-Transfer-Encoding; b=XjKOJ/TMv3sUy+j30jdJA/lBzELR5g/FgIJD54nwDlPDzprLIksZkb8mSv1ECJN/gPtwA5iopEachhDsFNjSwTtwtlny0YSv4m1ZGJnty3sIkFIX++zgbzlpzC2HwB8NpRb/RDS+XsQIjjYZpUyFtUI+Of7WI09LK2hELkHy2j4= ; DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rogers.com; s=s1024; t=1326147210; bh=JfqwV5njsIzKydWwW4+75CvFDOYxink7WDfLAhULZUM=; h=X-Yahoo-Newman-Property:X-YMail-OSG:X-Yahoo-SMTP:Received:Message-ID:Date:From:Reply-To:User-Agent:MIME-Version:To:Subject:References:In-Reply-To:X-Enigmail-Version:Content-Type:Content-Transfer-Encoding; b=k/ct/H2wsXP/ihS9K4X9ftLedoyqEKMdX1vySomX7PJH8aYgYf3kIeb9N6sWy5JZvtKIFuKXZp7q4DuzD7MleV3BbgXvX/AEDcvds9Kgir5PRfhPuTIFgrJC3y7jt9CyAlPc43izHvc9352nudJUdES2P7F5k299eb06KGAcQs0= X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: NPQG2v8VM1mc7MqvnraN54A_JVwQLtWh_KGHr_a1R_3L8bo .6YSFnbuDbTdhwkRYHnmvdN4fdaTVVgtJpZGcUznGP5JSltTtdjSv3D50U6w rAPqxH4SE5O2_34szB3e2umUxI7Qjy4BCAAwuwG5HgZZ1AZewBxYCWfdyrz7 8zsdFvbwe3nByo6LRpZSFkHZga661aKVn4BLBooxWG7ZI5w4ajSFGXX6fAJO 2o2FieGxLH0kbPzw6._ZH5JrxlYJqpBjJHxP5t8LVVANbFkZNC7i.HE1b1Ch uRF.NkQggt17N5pxwMbA1mhiMoG396weeGKyMMSykGQ2crFoWrnOljsBBIhW X4NG1hURDRLK0ES1bEKTirAtISXd7epemdnC994MRDUj8dPsMGD7W1U5LTE5 l304blVUNyIGX3_ZFKYO8AewIJ_eb X-Yahoo-SMTP: sltvjZWswBCRD.ElTuB1l9j6s9wRYPpuyTNWOE5oEg-- Received: from [192.168.1.102] (davec-b@72.136.202.103 with plain) by smtp105.rog.mail.gq1.yahoo.com with SMTP; 09 Jan 2012 14:13:29 -0800 PST Message-ID: <4F0B673A.4050505@rogers.com> Date: Mon, 09 Jan 2012 17:16:26 -0500 From: David Collier-Brown User-Agent: Thunderbird 2.0.0.18 (X11/20081119) MIME-Version: 1.0 To: bloat@lists.bufferbloat.net References: In-Reply-To: X-Enigmail-Version: 0.96.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: [Bloat] Re: calculating baseline latency properly? X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list Reply-To: davecb@spamcop.net List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 09 Jan 2012 22:13:33 -0000 Dave Taht wrote: > In measuring ping RTT rather than arrival time elsewhere (which I plan > to do with RTP at some point), there's actually two variables in play > send and return time... > > So should a RTT latency under load calculation remove the baseline latency > thusly: > > latency_improvement = > (ping_RTT - baseline_ping_rtt) / (new_ping_RTT - baseline_ping_rtt) > > factor 344 improvement > > OR keep it: > > latency_improvement = > (ping_RTT) / (new_ping_RTT) > > factor 180 improvement... > > or would there be another way to compensate for it that made sense? > If the improvement in the *baseline* ping times is part of the improvement you're seeing, it's fair to include it in the calculation. In other words, if it's causal, it's golden. If you're unsure, leave it out. --dave (random capacity-planning guy) c-b -- David Collier-Brown, | Always do right. This will gratify System Programmer and Author | some people and astonish the rest davecb@spamcop.net | -- Mark Twain (416) 223-8968