From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from tuna.sandelman.ca ([209.87.249.19]:40324 "EHLO tuna.sandelman.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760449AbcDMMu0 (ORCPT ); Wed, 13 Apr 2016 08:50:26 -0400 From: Michael Richardson Subject: Re: UDP stress-testing In-Reply-To: <20160413082852.GA2428@omega> References: <5706C0D7.1040000@haw-hamburg.de> <20160407204125.GA4736@omega> <57075C35.5070206@haw-hamburg.de> <11304.1460505658@obiwan.sandelman.ca> <20160413082852.GA2428@omega> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha1; protocol="application/pgp-signature" Date: Wed, 13 Apr 2016 08:50:22 -0400 Message-ID: <16058.1460551822@obiwan.sandelman.ca> Sender: linux-wpan-owner@vger.kernel.org List-ID: To: Alexander Aring Cc: linux-wpan@vger.kernel.org, Peter Kietzmann --=-=-= Content-Type: text/plain Alexander Aring wrote: > _All_ current supported transceivers have on hardware side _one_ > framebuffer only. > I would agree 3-4 frames should keep the transmitter buffer, because > only one framebuffer, 250kBit (even slower on sub 1-GHz) and holding > 3-4 skb's in background. If we are counting frames rather than packets, then I agree that 3-4 is too low; we should accomodate 2-3 full-sized IPv6 packets worth of fragments. 1280 / 88 = 14 * 3 = 42. So I suggest somewhere between 32 and 48 as a good default. Well, we really ought to use the BQL to get the right number! https://lwn.net/Articles/469652/ > On most systems the qdisc default is pfifo (but I remember something > that systemd changed to fq_codel as default). yes, fq_codel is often the default now. > This will getting the queue full and with payload of 352 bytes it makes > fragments invalid because pfifo will drop some which is part of the > whole fragment. I had assumed that the fragmentation happened after the qdisc. > What I know is, when we drop one fragment, then we could drop every > fragment inside the queue which comes from the whole fragmented 6lowpan > packet. it seems this will not be handled currently. This is very important, and why I had assumed that fragmentation was afterwards. -- ] Never tell me the odds! | ipv6 mesh networks [ ] Michael Richardson, Sandelman Software Works | network architect [ ] mcr@sandelman.ca http://www.sandelman.ca/ | ruby on rails [ --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQEVAwUBVw5Ai4CLcPvd0N1lAQI8zwf+Pvn60HMF2mMHEuEcFZ3MQlUlbb9dAey3 rFz46H7Ku3LpFvKPeIzRz/vOBRN7R8Lb5kSHeDDXWtBGd+iCl341aWaKW5HbXElt MO3LdQMZhbBQZMg+/GgNhFRIH69p2JqmnuJXjdIh91a0Hoi2JnnpbgTKSAo6PJLB XMbbEP/vf+qwYCpcwSryZr4gd60ZRvBfGSYejbR/BK8ZsITKsOmsOnstlipbP/FR XX6Kg/IhpK21Mirtu5HRUzDZIGG8vUMVuYtN8ccjecMyAsv9SYixBqTmCI8+DHzk uuDo6mwEsE5P3E+9qZpWZIlgX1ATItYSHhOV9RBPYg2hjQoXTYEg4A== =Kbn5 -----END PGP SIGNATURE----- --=-=-=--