From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754493Ab1LMDYN (ORCPT ); Mon, 12 Dec 2011 22:24:13 -0500 Received: from mail-ey0-f174.google.com ([209.85.215.174]:35190 "EHLO mail-ey0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754043Ab1LMDYM (ORCPT ); Mon, 12 Dec 2011 22:24:12 -0500 Date: Tue, 13 Dec 2011 04:24:07 +0100 From: Richard Cochran To: Andy Lutomirski Cc: linux-kernel@vger.kernel.org, Kumar Sundararajan , john stultz , Arun Sharma , Peter Zijlstra , Ingo Molnar , Thomas Gleixner Subject: Re: [RFC 0/2] ABI for clock_gettime_ns Message-ID: <20111213032406.GA9604@netboy.at.omicron.at> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 12, 2011 at 05:26:36PM -0800, Andy Lutomirski wrote: > On x86-64, clock_gettime is so fast that the overhead converting to and > from nanoseconds is non-negligible. clock_gettime_ns is a different > interface that is potentially faster. If people like the ABI, I'll > implement an optimized version. I am not so interested in performance optimizations, but do I think offering time in nanoseconds is attractive from an application point of view. The timespec is impractical for everyone. While you are at it with new syscalls, why not make a clean break from POSIX and fix the uglies? - New name, to distance ourselves from POSIX (clock_ns_get?) - Family of calls, with set/get - Sub nanosecond field - TAI time base (or according to parameter?) Thanks, Richard