From owner-freebsd-questions Mon Nov 25 00:01:43 1996 Return-Path: owner-questions Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id AAA11537 for questions-outgoing; Mon, 25 Nov 1996 00:01:43 -0800 (PST) Received: from hq.icb.chel.su (hq.icb.chel.su [193.125.10.33]) by freefall.freebsd.org (8.7.5/8.7.3) with ESMTP id AAA11482; Mon, 25 Nov 1996 00:00:01 -0800 (PST) Received: (babkin@localhost) by hq.icb.chel.su (8.7.5/8.6.5) id MAA12915; Mon, 25 Nov 1996 12:54:38 +0500 (ESK) From: "Serge A. Babkin" Message-Id: <199611250754.MAA12915@hq.icb.chel.su> Subject: Re: dgb driver with interrupts To: mcgovern@spoon.beta.com (Brian J. McGovern) Date: Mon, 25 Nov 1996 12:54:38 +0500 (ESK) Cc: questions@freebsd.org, hackers@freebsd.org In-Reply-To: <199611240132.UAA13563@spoon.beta.com> from "Brian J. McGovern" at Nov 23, 96 08:32:22 pm X-Mailer: ELM [version 2.4 PL23] Content-Type: text Sender: owner-questions@freebsd.org X-Loop: FreeBSD.org Precedence: bulk > > I was looking over the dgb.c (driver file), and noticed that there is some > skeleton work for using the driver with interrupts. However, its been > effectively commented out with the #ifdef 0. Is it possible to switch this > driver to use interrupts, instead of polled io? And if so, should I expect > it work/what are the changes? No, you can't do it by enabling this part of driver. You anned to add the interrupt support in other parts of driver too. > I'm curious, because I'd like to use 3-4 of these boards in a PC to do > some SLIP and PPP testing, and would be looking for optimal throughput. I think the polling mode may give even better throughput than the interrupt mode under heavy load. The reason is that it takes very short time to check if some port on the cards needs serviceing. But it saves the interrupt overhead. Really the interrupt mode can only improve the answer times. The other problem with polling is that it runs at clock priority and disables other interrupts for this time so interrupts can help here. -SB