From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752512AbcHHR7U (ORCPT ); Mon, 8 Aug 2016 13:59:20 -0400 Received: from mail-pf0-f178.google.com ([209.85.192.178]:33501 "EHLO mail-pf0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752132AbcHHR7S (ORCPT ); Mon, 8 Aug 2016 13:59:18 -0400 Date: Mon, 08 Aug 2016 10:59:08 -0700 (PDT) Message-Id: <20160808.105908.301414649577514579.davem@davemloft.net> To: hejianet@gmail.com Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kuznet@ms2.inr.ac.ru, jmorris@namei.org, yoshfuji@linux-ipv6.org, kaber@trash.net Subject: Re: [RFC PATCH 2/3] net: Replace for_each_possible_cpu with for_each_online_cpu From: David Miller In-Reply-To: <1470651742-15195-3-git-send-email-hejianet@gmail.com> References: <1470651742-15195-1-git-send-email-hejianet@gmail.com> <1470651742-15195-3-git-send-email-hejianet@gmail.com> X-Mailer: Mew version 6.7 on Emacs 24.5 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jia He Date: Mon, 8 Aug 2016 18:22:21 +0800 > In PowerPC server with large number cpus, the loop index in smt=1 could be > reduced to 1/8 compared with smt=8. > Thus cache misses can be reduced. You can't do this, if cpus go down we still want to report the statistics they collected while they were up. So we must use the possible cpu list here.