From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Fw: 2.6.19-rc1: Volanomark slowdown Date: Tue, 7 Nov 2006 11:25:55 -0800 Message-ID: <20061107112555.60b52715@freekitty> Reply-To: Tim Chen Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org Return-path: Received: from smtp.osdl.org ([65.172.181.4]:20880 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S1752449AbWKGT00 (ORCPT ); Tue, 7 Nov 2006 14:26:26 -0500 To: John Heffner , "David S. Miller" Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Begin forwarded message: Date: Tue, 07 Nov 2006 10:32:34 -0800 From: Tim Chen Newsgroups: linux.dev.kernel Subject: 2.6.19-rc1: Volanomark slowdown The patch [TCP]: Send ACKs each 2nd received segment commit: 1ef9696c909060ccdae3ade245ca88692b49285b http://kernel.org/git/? p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=1ef9696c909060ccdae3ade245ca88692b49285b reduced Volanomark benchmark throughput by 10%. This is because Volanomark sends short message (<100 bytes) on its TCP connections. This patch increases the number of ACKs traffic by 3.5 times. By adopting this patch, we assume that with small segment, having short delay is important enough that we are willing to reduce bandwidth with more ACKs. Is there any real application out there that this new behavior could be a concern? Tim - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ -- Stephen Hemminger