From owner-freebsd-hackers Thu Dec 23 23:21:31 1999 Delivered-To: freebsd-hackers@freebsd.org Received: from mass.cdrom.com (castles558.castles.com [208.214.165.122]) by hub.freebsd.org (Postfix) with ESMTP id 381371514F for ; Thu, 23 Dec 1999 23:21:28 -0800 (PST) (envelope-from msmith@mass.cdrom.com) Received: from mass.cdrom.com (localhost [127.0.0.1]) by mass.cdrom.com (8.9.3/8.9.3) with ESMTP id XAA02292; Thu, 23 Dec 1999 23:25:50 -0800 (PST) (envelope-from msmith@mass.cdrom.com) Message-Id: <199912240725.XAA02292@mass.cdrom.com> X-Mailer: exmh version 2.1.1 10/15/1999 To: Joe McGuckin Cc: hackers@freebsd.org Subject: Re: motherboard serial port dropping chars ? In-reply-to: Your message of "Mon, 20 Dec 1999 20:23:11 PST." <199912210423.UAA76829@monk.via.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Thu, 23 Dec 1999 23:25:50 -0800 From: Mike Smith Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > > I have an application where I need to receive data constantly on > a serial port at 38,400. When we write the data to a database, > we constantly see dropped chars on the incoming serial port. > > Is the stock PC serial hardware capable of sustained thruput at > 38.4K? Easily, modulo other peripherals which can interfere with this. > Is there an ioctl option or something to improve the buffering > on the serial ports ? No. You probably have a PCI peripheral that's hogging the bus for sufficiently long to cause the FIFO in your serial device to overflow. IDE disks doing DMA are prime culprits for this, and X servers have been known to cause it as well (by disabling interrupts entirely). -- \\ Give a man a fish, and you feed him for a day. \\ Mike Smith \\ Tell him he should learn how to fish himself, \\ msmith@freebsd.org \\ and he'll hate you for a lifetime. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message