From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932329AbWFSAPp (ORCPT ); Sun, 18 Jun 2006 20:15:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932327AbWFSAPo (ORCPT ); Sun, 18 Jun 2006 20:15:44 -0400 Received: from omx1-ext.sgi.com ([192.48.179.11]:43473 "EHLO omx1.americas.sgi.com") by vger.kernel.org with ESMTP id S932329AbWFSAPo (ORCPT ); Sun, 18 Jun 2006 20:15:44 -0400 Date: Sun, 18 Jun 2006 17:15:11 -0700 From: Paul Jackson To: Andi Kleen Cc: discuss@x86-64.org, linux-kernel@vger.kernel.org, libc-alpha@sourceware.org, vojtech@suse.cz Subject: Re: FOR REVIEW: New x86-64 vsyscall vgetcpu() Message-Id: <20060618171511.e0e6de26.pj@sgi.com> In-Reply-To: <200606140942.31150.ak@suse.de> References: <200606140942.31150.ak@suse.de> Organization: SGI X-Mailer: Sylpheed version 2.2.4 (GTK+ 2.8.3; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Interesting - thanks Andi. I had one of my colleagues at SGI lobby me hard for such a facility. I'll see if I can get him on this thread to better explain what he wanted it for. Roughly, he was looking to support something resembling the kernel's per-cpu data in userland library code for high performance scientific number crunching, for things like statistics gathering and perhaps (not sure of this) reduce locking costs. I see "x86-64" in the Subject. I don't see why this facility is arch-specific. Could it work on any arch, ia64 being the one of interest to me? I have some ignorance on your references to "CPUID(1)". I don't recall what it is. The only command so named I find on my systems are a Windows command from the year 1999. I doubt that's it. You wrote: > As you can see CPUID(1) is always very slow but but I don't see any stats above the comment mentioning CPUID(1), so ... er eh ... no I don't see. -- I won't rest till it's the best ... Programmer, Linux Scalability Paul Jackson 1.925.600.0401