Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262284AbTEIDky (ORCPT ); Thu, 8 May 2003 23:40:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262285AbTEIDky (ORCPT ); Thu, 8 May 2003 23:40:54 -0400 Received: from zcars04e.nortelnetworks.com ([47.129.242.56]:44752 "EHLO zcars04e.nortelnetworks.com") by vger.kernel.org with ESMTP id S262284AbTEIDkx (ORCPT ); Thu, 8 May 2003 23:40:53 -0400 Message-ID: <3EBB25FD.7060809@nortelnetworks.com> Date: Thu, 08 May 2003 23:52:29 -0400 X-Sybari-Space: 00000000 00000000 00000000 From: Chris Friesen User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.8) Gecko/20020204 X-Accept-Language: en-us MIME-Version: 1.0 To: root@chaos.analogic.com Cc: William Lee Irwin III , Davide Libenzi , Linux Kernel Mailing List Subject: Re: how to measure scheduler latency on powerpc? realfeel doesn't work due to /dev/rtc issues References: <3EBAD63C.4070808@nortelnetworks.com> <20030509001339.GQ8978@holomorphy.com> <20030509003825.GR8978@holomorphy.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1244 Lines: 33 Richard B. Johnson wrote: > On Thu, 8 May 2003, William Lee Irwin III wrote: >>>>Why would you want to use an interrupt? Just count jiffies in sched.c 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. > Does it have a printer port like the Intel machines? 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. Chris -- Chris Friesen | MailStop: 043/33/F10 Nortel Networks | work: (613) 765-0557 3500 Carling Avenue | fax: (613) 765-2986 Nepean, ON K2H 8E9 Canada | email: cfriesen@nortelnetworks.com - 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/