From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751242AbVHVX2O (ORCPT ); Mon, 22 Aug 2005 19:28:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751291AbVHVX2O (ORCPT ); Mon, 22 Aug 2005 19:28:14 -0400 Received: from fmr22.intel.com ([143.183.121.14]:16105 "EHLO scsfmr002.sc.intel.com") by vger.kernel.org with ESMTP id S1751242AbVHVX2M (ORCPT ); Mon, 22 Aug 2005 19:28:12 -0400 Date: Mon, 22 Aug 2005 16:27:28 -0700 From: tony.luck@intel.com Message-Id: <200508222327.j7MNRSBR020922@agluck-lia64.sc.intel.com> To: Andrew Morton Cc: davem@davemloft.net, jasonuhl@sgi.com, linux-kernel@vger.kernel.org Subject: Re: CONFIG_PRINTK_TIME woes In-Reply-To: <20050822153838.186ac336.akpm@osdl.org> References: <200508221742.j7MHgMJI020020@agluck-lia64.sc.intel.com> <20050822.132052.65406121.davem@davemloft.net> <20050822203306.GA897956@dragonfly.engr.sgi.com> <20050822.134226.35468933.davem@davemloft.net> <200508222233.j7MMXGWj020872@agluck-lia64.sc.intel.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org >Ah, thanks. Presumably it'll be considerably longer with %d's and %s's in >there. But still, ~10 usecs is good resolution for I/O operations. The variation in times from one call to the next seems to be greater than the time to evaluate 4 "%d" arguments. So we are back to how to get a timestamp in printk(). Earlier I said that it would be possible to provide a simplified do_gettimeofday() call that met the no locks requirement. I still think this is possible, but most architectures would only get jiffie resolution from this (only ia64, sparc64 and HPET users have time interpolators registered). -Tony