From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762600AbWLKAiI (ORCPT ); Sun, 10 Dec 2006 19:38:08 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1762594AbWLKAiH (ORCPT ); Sun, 10 Dec 2006 19:38:07 -0500 Received: from ns.suse.de ([195.135.220.2]:57265 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762595AbWLKAiG (ORCPT ); Sun, 10 Dec 2006 19:38:06 -0500 Date: Mon, 11 Dec 2006 01:39:04 +0100 From: Andrea Arcangeli To: john stultz Cc: ak@suse.de, linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@elte.hu, Suleiman Souhlal Subject: rdtscp vgettimeofday Message-ID: <20061211003904.GB5366@opteron.random> References: <20061129025728.15379.50707.sendpatchset@localhost> <20061129025752.15379.14257.sendpatchset@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20061129025752.15379.14257.sendpatchset@localhost> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hello, As far as I can see, many changes happened but nobody has yet added the rdtscp support to x86-64. rdtscp finally solves the problem and it obsoletes hpet for timekeeping and it allows a fully userland gettimeofday running at maximum speed in userland. Before rdtscp we could never index the rdtsc offset in a proper index without being in kernel with preemption disabled, so it could never work reliably. What's the status of the DSO API? Does it break backwards compatibility or is the production glibc already capable of handling that new kernel API? I need rdtscp working on vsyscalls ASAP, but I should first understand if I need to base my code on top of the vDSO patch or if to fork it off in a dead branch to preserve backwards compatibility with current glibc userland. Thanks.