From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yair Gottdenker Subject: Increasing TCP initial cwnd Date: Mon, 26 Oct 2009 15:40:37 +0200 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 To: netdev@vger.kernel.org Return-path: Received: from mail-fx0-f218.google.com ([209.85.220.218]:36421 "EHLO mail-fx0-f218.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751824AbZJZNke (ORCPT ); Mon, 26 Oct 2009 09:40:34 -0400 Received: by fxm18 with SMTP id 18so12057792fxm.37 for ; Mon, 26 Oct 2009 06:40:38 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: Hi all, I am working on research project to control the sender initial congestion window size. I am trying to allow user space to set the initial congestion window size but with no luck. The sender always sends just 4 packets disregarding from the snd_cwnd. I am working on kernel version 2.6.31.3. I made the following changes: 1. tcp_ipv4.c -> in function tcp_v4_init_sock, changed from tp->snd_cwnd = 2 to tp->snd_cwnd = user_space_initial_cwnd. 2. tcp_output.c -> tcp_init_cwnd - to always return user_space_initial_cwnd. 3. tcp_cong.c -> tcp_slow_start- to always return user_space_initial_cwnd. Any help will be more than welcome. Yair