From mboxrd@z Thu Jan 1 00:00:00 1970 From: "=?UTF-8?q?Bendik=20R=C3=B8nning=20Opstad?=" Subject: [PATCH RFC v2 net-next 0/2] tcp: Redundant Data Bundling (RDB) Date: Mon, 23 Nov 2015 17:26:24 +0100 Message-ID: <1448295986-14576-1-git-send-email-bro.devel+kernel@gmail.com> References: <1445633413-3532-1-git-send-email-bro.devel+kernel@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Yuchung Cheng , Eric Dumazet , Neal Cardwell , Andreas Petlund , Carsten Griwodz , =?UTF-8?q?P=C3=A5l=20Halvorsen?= , Jonas Markussen , Kristian Evensen , Kenneth Klette Jonassen , =?UTF-8?q?Bendik=20R=C3=B8nning=20Opstad?= To: "David S. Miller" , Return-path: Received: from mail-lf0-f47.google.com ([209.85.215.47]:35082 "EHLO mail-lf0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753444AbbKWQ1S (ORCPT ); Mon, 23 Nov 2015 11:27:18 -0500 Received: by lfdl133 with SMTP id l133so29935646lfd.2 for ; Mon, 23 Nov 2015 08:27:17 -0800 (PST) In-Reply-To: <1445633413-3532-1-git-send-email-bro.devel+kernel@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: This is a request for comments. Redundant Data Bundling (RDB) is a mechanism for TCP aimed at reducing the latency for applications sending time-dependent data. Latency-sensitive applications or services, such as online games and remote desktop, produce traffic with thin-stream characteristics, characterized by small packets and a relatively high ITT. By bundling already sent data in packets with new data, RDB alleviates head-of-line blocking by reducing the need to retransmit data segments when packets are lost. RDB is a continuation on the work on latency improvements for TCP in Linux, previously resulting in two thin-stream mechanisms in the Linux kernel (https://github.com/torvalds/linux/blob/master/Documentation/networking= /tcp-thin.txt). The RDB implementation has been thoroughly tested, and shows significant latency reductions when packet loss occurs[1]. The tests show that, by imposing restrictions on the bundling rate, it can be mad= e not to negatively affect competing traffic in an unfair manner. Note: Current patch set depends on a recently submitted patch for tcp_skb_cb (tcp: refactor struct tcp_skb_cb: http://patchwork.ozlabs.or= g/patch/510674) These patches have been tested with as set of packetdrill scripts locat= ed at https://github.com/bendikro/packetdrill/tree/master/gtests/net/packetdr= ill/tests/linux/rdb (The tests require patching packetdrill with a new socket option: https://github.com/bendikro/packetdrill/commit/9916b6c53e33dd04329d29b7= d8baf703b2c2ac1b) Detailed info about the RDB mechanism can be found at http://mlab.no/blog/2015/10/redundant-data-bundling-in-tcp, as well as = in the paper "Latency and Fairness Trade-Off for Thin Streams using Redundant Data Bundling in TCP"[2]. [1] http://home.ifi.uio.no/paalh/students/BendikOpstad.pdf [2] http://home.ifi.uio.no/bendiko/rdb_fairness_tradeoff.pdf Changes: v2: * tcp-Add-DPIFL-thin-stream-detection-mechanism: * Change calculation in tcp_stream_is_thin_dpifl based on feedback from Eric Dumazet. * tcp-Add-Redundant-Data-Bundling-RDB: * Removed setting nonagle in do_tcp_setsockopt (TCP_RDB) to reduce complexity as commented by Neal Cardwell. * Cleaned up loss detection code in rdb_check_rtx_queue_loss Bendik R=C3=B8nning Opstad (2): tcp: Add DPIFL thin stream detection mechanism tcp: Add Redundant Data Bundling (RDB) Documentation/networking/ip-sysctl.txt | 23 +++ include/linux/skbuff.h | 1 + include/linux/tcp.h | 3 +- include/net/tcp.h | 35 +++++ include/uapi/linux/tcp.h | 1 + net/core/skbuff.c | 3 +- net/ipv4/Makefile | 3 +- net/ipv4/sysctl_net_ipv4.c | 35 +++++ net/ipv4/tcp.c | 16 +- net/ipv4/tcp_input.c | 3 + net/ipv4/tcp_output.c | 11 +- net/ipv4/tcp_rdb.c | 271 +++++++++++++++++++++++++= ++++++++ 12 files changed, 397 insertions(+), 8 deletions(-) create mode 100644 net/ipv4/tcp_rdb.c --=20 1.9.1