From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 18 Jul 2001 07:49:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 18 Jul 2001 07:49:34 -0400 Received: from mailserv.intranet.GR ([146.124.14.106]:24748 "EHLO mailserv.intranet.gr") by vger.kernel.org with ESMTP id ; Wed, 18 Jul 2001 07:49:23 -0400 Content-Type: text/plain; charset=US-ASCII From: anpol Organization: INTRACOM S.A. To: linux-kernel@vger.kernel.org Subject: Delayed acks in Linux 2.2.14 Date: Wed, 18 Jul 2001 14:52:59 -0400 X-Mailer: KMail [version 1.2] MIME-Version: 1.0 Message-Id: <01071814525900.00834@patdpd21.intranet.gr> Content-Transfer-Encoding: 7BIT Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi everyone, I am studying delayed acks in linux 2.2.14 and i come to the following conclusions. In bulk data transfer between two linux boxes i never saw a delayed ack. The server sends an ack every 2 full sized segments. This is fine but in transactional data transfer (e.g. a telnet session) i also do not see a delayed ack. What i see is this: 1. Client sends a character 2. Server echoes the character 3. Client sends an ack for the echo The time between segment 2 and 3 is never above 20ms even when i have a large RTT (say 560 ms). This is a small delay(??) but its not enough to say that the ack is delayed. I also could never see the max delay of HZ/2 on an ACK. So delaying an ack does not depend on the RTT of the connection. Is that correct? And if yes where does it depend? Has anyone seen the HZ/2 delay on an ACK? Thank you in advance Tasos p.s. please Cc your answer to my e-mail address