From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261671AbULNVkj (ORCPT ); Tue, 14 Dec 2004 16:40:39 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261672AbULNVkj (ORCPT ); Tue, 14 Dec 2004 16:40:39 -0500 Received: from mx1.redhat.com ([66.187.233.31]:57782 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S261671AbULNVkQ (ORCPT ); Tue, 14 Dec 2004 16:40:16 -0500 Message-ID: <41BF5D41.6030001@redhat.com> Date: Tue, 14 Dec 2004 13:38:09 -0800 From: Ulrich Drepper Organization: Red Hat, Inc. User-Agent: Mozilla Thunderbird 1.0 (X11/20041208) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Christoph Lameter CC: Roland McGrath , akpm@osdl.org, torvalds@osdl.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/7] cpu-timers: high-resolution CPU clocks for POSIX clock_* syscalls References: <200412140355.iBE3t7KL008040@magilla.sf.frob.com> In-Reply-To: X-Enigmail-Version: 0.89.5.0 X-Enigmail-Supports: pgp-inline, pgp-mime Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig4DC89F830BDC64559FFE7C2E" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig4DC89F830BDC64559FFE7C2E Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Christoph Lameter wrote: > Posix does not prescribe any access limitations for those clocks and as > far as I understand the standard, access to all process clocks needs to > be possible. And how exactly do you plan to address clocks of various threads in another process? Threads are only identified by the pthread_t descriptor. These values have no meaning outside the process the threads are in. The TIDs we use in the implementation cannot be used. They are an implementation detail and a thread might very well have different TIDs over time in future versions of the thread library. The pthread_getcpuclockid() and similar uses return clock IDs which are only meaningful in the calling process. Using the value in another process has undefined results. I.e., what Roland says is correct, the limitation is needed. -- ➧ Ulrich Drepper ➧ Red Hat, Inc. ➧ 444 Castro St ➧ Mountain View, CA ❖ --------------enig4DC89F830BDC64559FFE7C2E Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.6 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org iD8DBQFBv11B2ijCOnn/RHQRArFrAJ47rmmDMVZTkDayHcMrJY5Ey2xigACfarbF ceaYYCRSdI8dAsCy63kq48E= =FcSX -----END PGP SIGNATURE----- --------------enig4DC89F830BDC64559FFE7C2E--