Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S269107AbUIBW1V (ORCPT ); Thu, 2 Sep 2004 18:27:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S269156AbUIBWZP (ORCPT ); Thu, 2 Sep 2004 18:25:15 -0400 Received: from omx1-ext.sgi.com ([192.48.179.11]:41353 "EHLO omx1.americas.sgi.com") by vger.kernel.org with ESMTP id S269107AbUIBWVB (ORCPT ); Thu, 2 Sep 2004 18:21:01 -0400 Date: Thu, 2 Sep 2004 15:19:38 -0700 (PDT) From: Christoph Lameter X-X-Sender: clameter@schroedinger.engr.sgi.com To: john stultz cc: lkml , tim@physik3.uni-rostock.de, george anzinger , albert@users.sourceforge.net, Ulrich.Windl@rz.uni-regensburg.de, Len Brown , linux@dominikbrodowski.de, David Mosberger , Andi Kleen , paulus@samba.org, schwidefsky@de.ibm.com, jimix@us.ibm.com, keith maanthey , greg kh , Patricia Gaughen , Chris McDermott Subject: Re: [RFC][PATCH] new timeofday core subsystem (v.A0) In-Reply-To: <1094159379.14662.322.camel@cog.beaverton.ibm.com> Message-ID: References: <1094159238.14662.318.camel@cog.beaverton.ibm.com> <1094159379.14662.322.camel@cog.beaverton.ibm.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1232 Lines: 44 On Thu, 2 Sep 2004, john stultz wrote: > +struct timesource_t { > + char* name; > + int priority; > + cycle_t (*read)(void); > + cycle_t (*delta)(cycle_t now, cycle_t then); > + nsec_t (*cyc2ns)(cycle_t cycles, cycle_t* remainder); > +}; This is defining functions to be called for a timesource. Which means that the functionality for clock_gettime cannot be implemented as a fastcall anymore on IA64. The delta and the cyc2ns function are always the same. The compensation for jitter etc is always the same and can also be implemented generically. Could we change this to avoid the function calls. For example. struct timesource_t { char *name; int priority; int type; void *address; long long int frequency; } The functions are always delta = (now-then) cycle2ns = cycles * (NSEC_PER_SEC / frequency) + remainder types of time sources #define TIMESOURCE_CPU 0 #define TIMESOURCE_MMIO32 1 #define TIMESOURCE_MMIO64 2 #define TIMESOURCE_FUNCTION 3 /* To catch odd cases */ - 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/