From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net (mout.gmx.net [212.227.15.19]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "mout.gmx.net", Issuer "TeleSec ServerPass DE-1" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id 1FC0E21F29F for ; Sun, 25 May 2014 11:39:22 -0700 (PDT) Received: from hms-beagle.home.lan ([217.86.112.166]) by mail.gmx.com (mrgmx001) with ESMTPSA (Nemesis) id 0MO77c-1Wu7V40UuC-005ZWc; Sun, 25 May 2014 20:39:18 +0200 Content-Type: text/plain; charset=windows-1252 Mime-Version: 1.0 (Mac OS X Mail 6.6 \(1510\)) From: Sebastian Moeller In-Reply-To: Date: Sun, 25 May 2014 20:39:16 +0200 Content-Transfer-Encoding: quoted-printable Message-Id: <360688D7-8810-42F2-9FB1-BC0CD197993B@gmx.de> References: To: Dane Medic X-Mailer: Apple Mail (2.1510) X-Provags-ID: V03:K0:ms8Agjb+8A0JA4OOAbh+uiM+v5OPRkvpD7v7CM8bx9IlHIneeBx s/P3igk0i67L24ZdkUubjKDa0xm2jbvKM8p9TeTz3TJRUS1uo9ougtnYhxGlSwIVYgrZRRd zj2vaVrqkSrIdnQJc8endQ0MCRs07Wvlcq12mCnJYJybRhjHuEB3NvsmDm/uOmu/FZ6kVR8 mD6zEWGYi9qw+g4414dVg== Cc: cerowrt-devel@lists.bufferbloat.net Subject: Re: [Cerowrt-devel] Ubiquiti QOS X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 25 May 2014 18:39:22 -0000 Hi Dane, On May 25, 2014, at 08:17 , Dane Medic wrote: > Is it true that devices with less than 64 MB can't handle QOS? -> = https://lists.chambana.net/pipermail/commotion-dev/2014-May/001816.html I think this means that the commotion developers think that 64MB = are required. But it does not sound like they have first hand experience = so this is either hearsay, or commotions mesh networking is memory = intensive. On the openwrt side there seems no documentation of minim ram = requirements. Doing a quick back-of-the-envelop calculation here: openWRT qos has 4 tiers which run fq_codel in both directions so we have = 8 fq_codel instances, with each fq_codel having a limit of 10240 = packets, so worst case we expect: 4 * 2 * 10240 =3D 81920 packets at 1500bytes this equals 4 * 2 * 10240 * 1500 / (1024 * 1024) =3D 117.1875 MB this indeed is a bit heavy on a 32MB router, but honestly 64MB will not = really help you. Then again current openwrt has a limit off 800 instead = of 10240 so we end up at a worst case of: 4 * 2 * 800 * 1500 / (1024 * 1024) =3D 9.1552734375 MB which should still be possible with 32MB. (Note that typically fq_codel = does not fill its queues up to limit, but it still would be bad if a = router can easily be DOSed into OOM and rebooting=85) (For current cerowrt with simple.qos the worst case is: (1001 * 4 + 1000 * 13 + 800 * 12) * 1500 / (1024 * 1024) =3D = 38.0573272705 MB yet this still works quite well on a 64MB device (only 4 of these queues = are connected to the WAN interface though) One of the bigger issues with devices with small RAM is that often they = have relatively weak CPUs and I seem to recall that cerowrt tops out = around 60 to 70 Mbit/sec (total for ingress and egress) due to its = shaping performance. So unless you want to run commotion you might want to ask on the openwrt = list=85 Best Regards Sebastan =20 > _______________________________________________ > Cerowrt-devel mailing list > Cerowrt-devel@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/cerowrt-devel