From mboxrd@z Thu Jan 1 00:00:00 1970 From: Leslie Monis Subject: [PATCH net-next 5/8] net: sched: pie: add more conditions to auto-tune alpha and beta Date: Wed, 31 Oct 2018 21:49:29 +0530 Message-ID: <1541002772-28040-6-git-send-email-lesliemonis@gmail.com> References: <1541002772-28040-1-git-send-email-lesliemonis@gmail.com> Cc: netdev@vger.kernel.org, tahiliani@nitk.edu.in, dhavaljkhandla26@gmail.com, hrishihiraskar@gmail.com, bmanish15597@gmail.com, sdp.sachin@gmail.com To: jhs@mojatatu.com Return-path: Received: from mail-pl1-f193.google.com ([209.85.214.193]:36192 "EHLO mail-pl1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729287AbeKABSj (ORCPT ); Wed, 31 Oct 2018 21:18:39 -0400 Received: by mail-pl1-f193.google.com with SMTP id y11-v6so7531740plt.3 for ; Wed, 31 Oct 2018 09:19:58 -0700 (PDT) In-Reply-To: <1541002772-28040-1-git-send-email-lesliemonis@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: From: "Mohit P. Tahiliani" The update in drop probability depends on the parameters alpha and beta, which in turn reflect the current congestion level. However, the previous if-else cases were recommended when the supported bandwidth was up to 12 Mbps but, current data links support a much higher bandwidth, and the requirement for more bandwidth is in never-ending demand. Hence, RFC 8033 suggests using more if-else cases for better fine-tuning of parameters alpha and beta in order to control the congestion as much as possible. Signed-off-by: Mohit P. Tahiliani Signed-off-by: Dhaval Khandla Signed-off-by: Hrishikesh Hiraskar Signed-off-by: Manish Kumar B Signed-off-by: Sachin D. Patil Signed-off-by: Leslie Monis --- net/sched/sch_pie.c | 26 +++++++++++++++++++++++--- 1 file changed, 23 insertions(+), 3 deletions(-) diff --git a/net/sched/sch_pie.c b/net/sched/sch_pie.c index f4e189a..c84e91e 100644 --- a/net/sched/sch_pie.c +++ b/net/sched/sch_pie.c @@ -343,10 +343,30 @@ static void calculate_probability(struct Qdisc *sch) * appropriately 2) scaling down by 16 to come to 0-2 range. * Please see paper for details. * - * We scale alpha and beta differently depending on whether we are in - * light, medium or high dropping mode. + * We scale alpha and beta differently depending on how heavy the + * congestion is. */ - if (q->vars.prob < MAX_PROB / 100) { + if (q->vars.prob < MAX_PROB / 1000000) { + alpha = + (q->params.alpha * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 15; + beta = + (q->params.beta * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 15; + } else if (q->vars.prob < MAX_PROB / 100000) { + alpha = + (q->params.alpha * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 13; + beta = + (q->params.beta * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 13; + } else if (q->vars.prob < MAX_PROB / 10000) { + alpha = + (q->params.alpha * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 11; + beta = + (q->params.beta * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 11; + } else if (q->vars.prob < MAX_PROB / 1000) { + alpha = + (q->params.alpha * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 9; + beta = + (q->params.beta * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 9; + } else if (q->vars.prob < MAX_PROB / 100) { alpha = (q->params.alpha * (MAX_PROB / PSCHED_TICKS_PER_SEC)) >> 7; beta = -- 2.7.4