From owner-freebsd-questions@FreeBSD.ORG Sun Mar 27 14:50:51 2005 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id CA4C716A4CE for ; Sun, 27 Mar 2005 14:50:51 +0000 (GMT) Received: from wproxy.gmail.com (wproxy.gmail.com [64.233.184.205]) by mx1.FreeBSD.org (Postfix) with ESMTP id 5C07043D1F for ; Sun, 27 Mar 2005 14:50:51 +0000 (GMT) (envelope-from kirmizimantar@gmail.com) Received: by wproxy.gmail.com with SMTP id 69so105117wri for ; Sun, 27 Mar 2005 06:50:50 -0800 (PST) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:reply-to:to:subject:mime-version:content-type:content-transfer-encoding; b=MRJpqE7M7p8t7NrTB1h7XJ9MY8Wj+mD1KXk2YwFOwG0MNkBUGUnY2krBnySqwTo6scG54HgsvTvXOrVw3+K5g++UJ6E8J11ys4va4hfVZbhUPKKemcd19E4Yrg5MMmvcHtRFQChq2YDZYyTXnkT8WKCRY8AreGU9JW1wGmbeBQY= Received: by 10.54.34.62 with SMTP id h62mr362916wrh; Sun, 27 Mar 2005 06:50:50 -0800 (PST) Received: by 10.54.65.12 with HTTP; Sun, 27 Mar 2005 06:50:50 -0800 (PST) Message-ID: Date: Sun, 27 Mar 2005 14:50:50 +0000 From: Bahadir Balban To: freebsd-questions@freebsd.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: definition of soft/hard interrupts. X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list Reply-To: Bahadir Balban List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 27 Mar 2005 14:50:51 -0000 Hi, In "The design and implementation of 4.4BSD", the execution of workqueues, some timer events and scheduling are referred to as "software interrupts", as well as system calls. I thought only system calls would be in "soft interrupt" category as they are initiated with a software interrupt instruction. By my definition, a hardware interrupt is one that is notified by the interrupt controller, and to my knowledge, timer events are hardware interrupts. Am I wrong? There's also a softclock and hardclock defined. It is as if, an interrupt handler for an interrupt reported on the controller, is termed as "hard", but a low-priority workqueue initiated by a later timer event is called as a "software interrupt" here. The distinction here mainly being made by their "priority". Would you confirm this? In my opinion this isn't the way to put it and software interrupts should only mean interrupts initiated by interrupt instructions. All this is mentioned in pp. 56-57 in the book and extends to other parts. Many thanks for reading, Bahadir