Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751702AbWBMKMg (ORCPT ); Mon, 13 Feb 2006 05:12:36 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751707AbWBMKMg (ORCPT ); Mon, 13 Feb 2006 05:12:36 -0500 Received: from cantor2.suse.de ([195.135.220.15]:3221 "EHLO mx2.suse.de") by vger.kernel.org with ESMTP id S1751702AbWBMKMf (ORCPT ); Mon, 13 Feb 2006 05:12:35 -0500 To: "Ulrich Windl" Cc: linux-kernel@vger.kernel.org Subject: Re: 2.6.15:kernel/time.c: The Nanosecond and code duplication References: <43F05143.29965.5D3E74@Ulrich.Windl.rkdvmks1.ngate.uni-regensburg.de> From: Andi Kleen Date: 13 Feb 2006 11:12:32 +0100 In-Reply-To: <43F05143.29965.5D3E74@Ulrich.Windl.rkdvmks1.ngate.uni-regensburg.de> Message-ID: User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3 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: 1201 Lines: 27 "Ulrich Windl" writes: > but there's no POSIX like syscall interface > (clock_getres, clock_gettime, clock_settime) yet. % grep clock include/asm-x86_64/unistd.h #define __NR_clock_settime 227 __SYSCALL(__NR_clock_settime, sys_clock_settime) #define __NR_clock_gettime 228 __SYSCALL(__NR_clock_gettime, sys_clock_gettime) #define __NR_clock_getres 229 __SYSCALL(__NR_clock_getres, sys_clock_getres) #define __NR_clock_nanosleep 230 __SYSCALL(__NR_clock_nanosleep, sys_clock_nanosleep) Has been available for quite some time. However the calls are currently slower than gettimeofday and also don't use nanoseconds internally in all cases (depends on the architecture), but still microseconds. But I'm not sure it matters that much because the underlying timers are often not better than microseconds anyways and with nanoseconds you start to time even the inherent system call latency. -Andi - 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/