Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756318AbbDJSdc (ORCPT ); Fri, 10 Apr 2015 14:33:32 -0400 Received: from terminus.zytor.com ([198.137.202.10]:45011 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755844AbbDJSda (ORCPT ); Fri, 10 Apr 2015 14:33:30 -0400 Message-ID: <55281732.8080808@zytor.com> Date: Fri, 10 Apr 2015 11:32:18 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: Ingo Molnar CC: Denys Vlasenko , "Paul E. McKenney" , Linus Torvalds , Jason Low , Peter Zijlstra , Davidlohr Bueso , Tim Chen , Aswin Chandramouleeswaran , LKML , Borislav Petkov , Andy Lutomirski , Brian Gerst , Thomas Gleixner , Peter Zijlstra Subject: Re: [PATCH] x86: Align jump targets to 1 byte boundaries References: <20150409183926.GM6464@linux.vnet.ibm.com> <20150410090051.GA28549@gmail.com> <20150410091252.GA27630@gmail.com> <20150410092152.GA21332@gmail.com> <20150410111427.GA30477@gmail.com> <20150410112748.GB30477@gmail.com> <20150410120846.GA17101@gmail.com> <5527C700.3030405@redhat.com> <5527CD92.1080901@zytor.com> <20150410175407.GB6563@gmail.com> In-Reply-To: <20150410175407.GB6563@gmail.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 620 Lines: 18 On 04/10/2015 10:54 AM, Ingo Molnar wrote: > > Yeah, but the decoder stops if the prefetch crosses a cache line? So > it appears to be an interaction of the 16 byte prefetch window and > cache line boundaries? > I don't think it has anything to do with cache lines. Rather, you may lose a cycle if the first instruction bundle crosses into a new 16-byte chunk. -hpa -- 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/