Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262289AbTEIEOc (ORCPT ); Fri, 9 May 2003 00:14:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262290AbTEIEOc (ORCPT ); Fri, 9 May 2003 00:14:32 -0400 Received: from holomorphy.com ([66.224.33.161]:13469 "EHLO holomorphy") by vger.kernel.org with ESMTP id S262289AbTEIEOb (ORCPT ); Fri, 9 May 2003 00:14:31 -0400 Date: Thu, 8 May 2003 21:26:59 -0700 From: William Lee Irwin III To: Chris Friesen Cc: Davide Libenzi , Linux Kernel Mailing List Subject: Re: how to measure scheduler latency on powerpc? realfeel doesn't work due to /dev/rtc issues Message-ID: <20030509042659.GS8978@holomorphy.com> Mail-Followup-To: William Lee Irwin III , Chris Friesen , Davide Libenzi , Linux Kernel Mailing List References: <3EBAD63C.4070808@nortelnetworks.com> <20030509001339.GQ8978@holomorphy.com> <20030509003825.GR8978@holomorphy.com> <3EBB25FD.7060809@nortelnetworks.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3EBB25FD.7060809@nortelnetworks.com> Organization: The Domain of Holomorphy User-Agent: Mutt/1.5.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1027 Lines: 24 On Thu, 8 May 2003, William Lee Irwin III wrote: >>>>> Why would you want to use an interrupt? Just count jiffies in sched.c On Thu, May 08, 2003 at 11:52:29PM -0400, Chris Friesen wrote: > I'm trying to get a feel for the maximum time from an interrupt coming in > until the userspace handler gets notified. On intel you can program the > hardware to generate interupts through /dev/rtc. The powerpc doesn't seem > to support this. > Jiffies are not accurate enough, I am expecting max latencies in the 1-2 ms > range. > Unfortunately no. USB/Firewire/Ethernet on the desktop, ethernet/serial > for compactPCI. > I want to find an additional programmable interrupt source. It bites that > cheap PCs have this, and the powerpc doesn't. Try the timebase instead. -- wli - 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/