Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753815Ab0AITwN (ORCPT ); Sat, 9 Jan 2010 14:52:13 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752911Ab0AITwM (ORCPT ); Sat, 9 Jan 2010 14:52:12 -0500 Received: from mx.treblig.org ([80.68.94.177]:46657 "EHLO mx.treblig.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752962Ab0AITwL (ORCPT ); Sat, 9 Jan 2010 14:52:11 -0500 Date: Sat, 9 Jan 2010 19:46:55 +0000 From: "Dr. David Alan Gilbert" To: "Paul G. Allen" Cc: Samuel Thibault , linux-kernel Subject: Re: Linux Serial Performance Message-ID: <20100109194655.GA28639@gallifrey> References: <20100109191025.GK4757@const.famille.thibault.fr> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Chocolate: 70 percent or better cocoa solids preferably X-Operating-System: Linux/2.6.31.5-kvm-i386-2009-10-30 (i686) X-Uptime: 19:44:24 up 55 days, 2:54, 2 users, load average: 0.06, 0.03, 0.01 User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1414 Lines: 34 * Paul G. Allen (pgallen@gmail.com) wrote: > Well, as far as I know. Same code on both systems. The embedded device > operates at 115200, 8N1, no flow control. It uses RPC/SLIP protocol > for commands and data. They talk to each other, but the Linux system > just takes forever to send the data. What does the RPC/SLIP - the app or the Kernel? If you have no flow control is it possible that someone is dropping a byte somewhere any recovering? If your device is set at the right speed (check with stty -a < /dev/ttyS??? ) then what speed does : dd if=/dev/zero of=/dev/ttyS??? bs=1 count=10000 show, for my line set at 9k6 (on ttyS0) it's showing 1.0kB/s which seems about right. What's the serial card - is it an onboard card or a PCI plug in, I've seen problems on Linux a few times where the device driver has the speed of some plugin cards out by a factor of 8. Dave -- -----Open up your eyes, open up your mind, open up your code ------- / Dr. David Alan Gilbert | Running GNU/Linux on Alpha,68K| Happy \ \ gro.gilbert @ treblig.org | MIPS,x86,ARM,SPARC,PPC & HPPA | In Hex / \ _________________________|_____ http://www.treblig.org |_______/ -- 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/