From owner-freebsd-arm@FreeBSD.ORG Wed May 8 09:18:56 2013 Return-Path: Delivered-To: freebsd-arm@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id 3558FDEA for ; Wed, 8 May 2013 09:18:56 +0000 (UTC) (envelope-from peter@rulingia.com) Received: from vps.rulingia.com (host-122-100-2-194.octopus.com.au [122.100.2.194]) by mx1.freebsd.org (Postfix) with ESMTP id AC0316E for ; Wed, 8 May 2013 09:18:54 +0000 (UTC) Received: from server.rulingia.com (c220-239-237-213.belrs5.nsw.optusnet.com.au [220.239.237.213]) by vps.rulingia.com (8.14.5/8.14.5) with ESMTP id r488x6NV099027 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Wed, 8 May 2013 18:59:07 +1000 (EST) (envelope-from peter@rulingia.com) X-Bogosity: Ham, spamicity=0.000000 Received: from server.rulingia.com (localhost.rulingia.com [127.0.0.1]) by server.rulingia.com (8.14.5/8.14.5) with ESMTP id r488x1lo098681 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Wed, 8 May 2013 18:59:01 +1000 (EST) (envelope-from peter@server.rulingia.com) Received: (from peter@localhost) by server.rulingia.com (8.14.5/8.14.5/Submit) id r488x1p1098680 for freebsd-arm@freebsd.org; Wed, 8 May 2013 18:59:01 +1000 (EST) (envelope-from peter) Date: Wed, 8 May 2013 18:59:01 +1000 From: Peter Jeremy To: freebsd-arm@freebsd.org Subject: Sawtooth ping RTT on RPi Message-ID: <20130508085901.GA90732@server.rulingia.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="VbJkn9YxBvnuCH5J" Content-Disposition: inline X-PGP-Key: http://www.rulingia.com/keys/peter.pgp User-Agent: Mutt/1.5.21 (2010-09-15) X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Porting FreeBSD to the StrongARM Processor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 08 May 2013 09:18:56 -0000 --VbJkn9YxBvnuCH5J Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable I've noticed a sawtooth-shaped cyclic pattern in ping RTTs to my RPi (running r249590M): 64 bytes from 192.168.123.231: icmp_seq=3D22 ttl=3D64 time=3D1.321 ms 64 bytes from 192.168.123.231: icmp_seq=3D23 ttl=3D64 time=3D10.312 ms 64 bytes from 192.168.123.231: icmp_seq=3D24 ttl=3D64 time=3D9.328 ms 64 bytes from 192.168.123.231: icmp_seq=3D25 ttl=3D64 time=3D8.335 ms 64 bytes from 192.168.123.231: icmp_seq=3D26 ttl=3D64 time=3D7.411 ms 64 bytes from 192.168.123.231: icmp_seq=3D27 ttl=3D64 time=3D6.448 ms 64 bytes from 192.168.123.231: icmp_seq=3D28 ttl=3D64 time=3D5.497 ms 64 bytes from 192.168.123.231: icmp_seq=3D29 ttl=3D64 time=3D4.508 ms 64 bytes from 192.168.123.231: icmp_seq=3D30 ttl=3D64 time=3D3.540 ms 64 bytes from 192.168.123.231: icmp_seq=3D31 ttl=3D64 time=3D2.588 ms 64 bytes from 192.168.123.231: icmp_seq=3D32 ttl=3D64 time=3D1.635 ms 64 bytes from 192.168.123.231: icmp_seq=3D33 ttl=3D64 time=3D0.738 ms 64 bytes from 192.168.123.231: icmp_seq=3D34 ttl=3D64 time=3D9.770 ms 64 bytes from 192.168.123.231: icmp_seq=3D35 ttl=3D64 time=3D8.805 ms 64 bytes from 192.168.123.231: icmp_seq=3D36 ttl=3D64 time=3D7.833 ms 64 bytes from 192.168.123.231: icmp_seq=3D37 ttl=3D64 time=3D6.843 ms 64 bytes from 192.168.123.231: icmp_seq=3D38 ttl=3D64 time=3D5.869 ms This doesn't appear with Linux (which has a RTT of 0.42ms with very little variance). What is causing the RTT pattern on FreeBSD? Haw does Linux manage to respond so much faster? --=20 Peter Jeremy --VbJkn9YxBvnuCH5J Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (FreeBSD) iEYEARECAAYFAlGKE9UACgkQ/opHv/APuIfvZQCgg62OWwxeBZwSPXeSvSVJz5Yb 53UAoILLTeYfxPSIo7dUR4PqDQhfYIU9 =Zqk+ -----END PGP SIGNATURE----- --VbJkn9YxBvnuCH5J--