From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932078Ab2EJJmG (ORCPT ); Thu, 10 May 2012 05:42:06 -0400 Received: from merlin.infradead.org ([205.233.59.134]:42811 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755144Ab2EJJmE convert rfc822-to-8bit (ORCPT ); Thu, 10 May 2012 05:42:04 -0400 Message-ID: <1336642145.2527.79.camel@twins> Subject: Re: [PATCH v4 4/7] x86/tlb: fall back to flush all when meet a THP large page From: Peter Zijlstra To: Alex Shi Cc: rob@landley.net, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, arnd@arndb.de, rostedt@goodmis.org, fweisbec@gmail.com, jeremy@goop.org, gregkh@linuxfoundation.org, borislav.petkov@amd.com, riel@redhat.com, luto@mit.edu, avi@redhat.com, len.brown@intel.com, dhowells@redhat.com, fenghua.yu@intel.com, ak@linux.intel.com, cpw@sgi.com, steiner@sgi.com, akpm@linux-foundation.org, penberg@kernel.org, hughd@google.com, rientjes@google.com, kosaki.motohiro@jp.fujitsu.com, n-horiguchi@ah.jp.nec.com, paul.gortmaker@windriver.com, trenn@suse.de, tj@kernel.org, oleg@redhat.com, axboe@kernel.dk, kamezawa.hiroyu@jp.fujitsu.com, viro@zeniv.linux.org.uk, linux-kernel@vger.kernel.org Date: Thu, 10 May 2012 11:29:05 +0200 In-Reply-To: <1336626013-28413-5-git-send-email-alex.shi@intel.com> References: <1336626013-28413-1-git-send-email-alex.shi@intel.com> <1336626013-28413-5-git-send-email-alex.shi@intel.com> Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-Mailer: Evolution 3.2.2- Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2012-05-10 at 13:00 +0800, Alex Shi wrote: > We don't need to flush large pages by PAGE_SIZE step, that just waste > time. and actually, large page don't need 'invlpg' optimizing according > to our macro benchmark. So, just flush whole TLB is enough for them. > > The following result is tested on a 2CPU * 4cores * 2HT NHM EP machine, > with THP 'always' setting. What does it do when you disable THP? That has_large_page() thing is a massive amount of pointer chasing..