From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:48724 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728528AbeLTApZ (ORCPT ); Wed, 19 Dec 2018 19:45:25 -0500 Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id wBK0U64i014711 for ; Wed, 19 Dec 2018 19:45:24 -0500 Received: from e13.ny.us.ibm.com (e13.ny.us.ibm.com [129.33.205.203]) by mx0a-001b2d01.pphosted.com with ESMTP id 2pfw03aa79-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 19 Dec 2018 19:45:24 -0500 Received: from localhost by e13.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 20 Dec 2018 00:45:23 -0000 Date: Wed, 19 Dec 2018 16:45:25 -0800 From: "Paul E. McKenney" Subject: Re: Parallel programming book query Reply-To: paulmck@linux.ibm.com References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Message-Id: <20181220004525.GZ4170@linux.ibm.com> Sender: perfbook-owner@vger.kernel.org List-ID: To: Mark Morrissey Cc: alexey.roytman@oracle.com, perfbook@vger.kernel.org On Mon, Dec 17, 2018 at 01:04:37PM -0800, Mark Morrissey wrote: > Hi Paul, > > I am looking at your parallel programming book, 12/5/2018 version. In > formula E.6, you use the floor function rather than the ceiling function. > Is this deliberate or perhaps in error? Good question! The intent is that the "+ s - 1" in the numerator does the upwards part of the rounding, and the floor function does the rest. Or am I missing something here? It should be possible to express this in terms of the ceiling function, though that would be further removed from C code implementing this equation. Adding Alexey and the list on CC. This is on page 423 (PDF page 435) of https://mirrors.edge.kernel.org/pub/linux/kernel/people/paulmck/perfbook/perfbook.2018.12.08a.pdf Thanx, Paul