Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263576AbUCTX7J (ORCPT ); Sat, 20 Mar 2004 18:59:09 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263577AbUCTX7J (ORCPT ); Sat, 20 Mar 2004 18:59:09 -0500 Received: from alt.aurema.com ([203.217.18.57]:14732 "EHLO smtp.sw.oz.au") by vger.kernel.org with ESMTP id S263576AbUCTX7E (ORCPT ); Sat, 20 Mar 2004 18:59:04 -0500 Message-ID: <405CDA9C.6090109@aurema.com> Date: Sun, 21 Mar 2004 10:58:20 +1100 From: Peter Williams Organization: Aurema Pty Ltd User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030624 Netscape/7.1 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Albert Cahalan CC: Arjan van de Ven , ak@muc.de, Richard.Curnow@superh.com, aeb@cwi.nl, linux-kernel mailing list , Albert Cahalan Subject: Re: finding out the value of HZ from userspace References: <1079453698.2255.661.camel@cube> <20040320095627.GC2803@devserv.devel.redhat.com> <1079794457.2255.745.camel@cube> In-Reply-To: <1079794457.2255.745.camel@cube> 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: 1557 Lines: 42 Albert Cahalan wrote: > On Sat, 2004-03-20 at 04:56, Arjan van de Ven wrote: > >>On Tue, Mar 16, 2004 at 11:14:59AM -0500, Albert Cahalan wrote: >> >>>>there is one. Nothing uses it >>>>(sysconf() provides this info) >>> >>>If you have a recent glibc on a recent kernel, it might. >>>You could also get a -1 or a supposed ABI value that >>>has nothing to do with the kernel currently running. >>>The most reliable way is to first look around on the >>>stack in search of ELF notes, and then fall back to >>>some horribly gross hacks as needed. >> >>eh sysconf() is the nice way to get to the ELF notes >>instead of having to grovel yourself. > > > Unless there is some hidden feature that lets > me specify the ELF note number directly, no way. > > The sysconf(_SC_CLK_TCK) call does not return an > error code when used on a 2.2.xx i386 kernel. > You get an arbitrary value that fails for ARM, > Alpha, and any system with modified HZ. As Linux is supposed to be POSIX compliant this is a bug and should be fixed. Peter -- Dr Peter Williams, Chief Scientist peterw@aurema.com Aurema Pty Limited Tel:+61 2 9698 2322 PO Box 305, Strawberry Hills NSW 2012, Australia Fax:+61 2 9699 9174 79 Myrtle Street, Chippendale NSW 2008, Australia http://www.aurema.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/