Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756537AbYKTRqS (ORCPT ); Thu, 20 Nov 2008 12:46:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752505AbYKTRqI (ORCPT ); Thu, 20 Nov 2008 12:46:08 -0500 Received: from wf-out-1314.google.com ([209.85.200.175]:31716 "EHLO wf-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750969AbYKTRqF (ORCPT ); Thu, 20 Nov 2008 12:46:05 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=YAUiAg41qf4xOo8pWwCKEerL4CBQC0CMxeieqhA1wh+5h1+Nc2TtGMGy98hr5nmc5i TcLg86SQ1AtfYLqKeKBLlIrmL1SNCKV0mHNN2/pAl4aaA7iXP+ggUdFxcy09fF/curfa 6ssXZf2ZFq4QFE5SVQ+g3hdgTqIxaU3P0eqsI= Message-ID: <87a5b0800811200946m4b58db6aoe91bfc45c38982bb@mail.gmail.com> Date: Thu, 20 Nov 2008 17:46:04 +0000 From: "Will Newton" To: "Tim Bird" Subject: Re: [PATCH] init/main.c: Use ktime accessor function in initcall_debug code. Cc: linux-kernel , "Andrew Morton" In-Reply-To: <4925A0BC.7050207@am.sony.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <87a5b0800811200647t4de76a2ah683ac6083014d061@mail.gmail.com> <4925A0BC.7050207@am.sony.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1214 Lines: 34 On Thu, Nov 20, 2008 at 5:39 PM, Tim Bird wrote: > Will Newton wrote: >> The initcall_debug code access the tv64 member of ktime. This won't work >> correctly for large deltas on platforms that don't use the scalar ktime >> implementation. > > In principle I see no problem with this. But as a matter of > practice it may be overkill. Possibly, but it makes the code clearer I think. > How big does the delta have to be for this to be a problem? > And how much overhead does ktime_to_ns() add? Deltas over a second will be incorrect. I have serial8250_init taking 8 seconds at the moment, so that isn't unheard of. On scalar ktime architectures it should be zero, on others a multiply and an add (it's an inline). I wouldn't call it a fast path though. > -- Tim > > ============================= > Tim Bird > Architecture Group Chair, CE Linux Forum > Senior Staff Engineer, Sony Corporation of America > ============================= > > -- 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/