From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yuchung Cheng Subject: [PATCH net-next 0/4] new mechanism to ACK immediately Date: Thu, 9 Aug 2018 09:38:08 -0700 Message-ID: <20180809163812.58365-1-ycheng@google.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Cc: netdev@vger.kernel.org, ncardwell@google.com, brakmo@fb.com, weiwan@google.com, Yuchung Cheng To: davem@davemloft.net, edumazet@google.com Return-path: Received: from mail-pf1-f178.google.com ([209.85.210.178]:44139 "EHLO mail-pf1-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730419AbeHITD7 (ORCPT ); Thu, 9 Aug 2018 15:03:59 -0400 Received: by mail-pf1-f178.google.com with SMTP id k21-v6so3090250pff.11 for ; Thu, 09 Aug 2018 09:38:19 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: This patch is a follow-up feature improvement to the recent fixes on the performance issues in ECN (delayed) ACKs. Many of the fixes use tcp_enter_quickack_mode routine to force immediate ACKs. However the routine also reset tracking interactive session. This is not ideal because these immediate ACKs are required by protocol specifics unrelated to the interactiveness nature of the application. This patch set introduces a new flag to send a one-time immediate ACK without changing the status of interactive session tracking. With this patch set the immediate ACKs are generated upon these protocol states: 1) When a hole is repaired 2) When CE status changes between subsequent data packets received 3) When a data packet carries CWR flag Yuchung Cheng (4): tcp: mandate a one-time immediate ACK tcp: avoid resetting ACK timer in DCTCP tcp: always ACK immediately on hole repairs tcp: avoid resetting ACK timer upon receiving packet with ECN CWR flag include/net/inet_connection_sock.h | 3 ++- net/ipv4/tcp_dctcp.c | 4 ++-- net/ipv4/tcp_input.c | 16 +++++++++------- 3 files changed, 13 insertions(+), 10 deletions(-) -- 2.18.0.597.ga71716f1ad-goog