From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754238Ab3LSPqK (ORCPT ); Thu, 19 Dec 2013 10:46:10 -0500 Received: from mail.skyhub.de ([78.46.96.112]:35911 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753709Ab3LSPqH (ORCPT ); Thu, 19 Dec 2013 10:46:07 -0500 Date: Thu, 19 Dec 2013 16:45:57 +0100 From: Borislav Petkov To: "H. Peter Anvin" Cc: Ingo Molnar , Len Brown , x86@kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, Len Brown , stable@vger.kernel.org, Linus Torvalds , Thomas Gleixner , Peter Zijlstra , Mike Galbraith Subject: Re: [PATCH] x86 idle: repair large-server 50-watt idle-power regression Message-ID: <20131219154557.GC26289@pd.tnic> References: <20131219122257.GC11279@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 19, 2013 at 06:40:41AM -0800, H. Peter Anvin wrote: > ... or just use static_cpu_has() maybe? Right, if we can get the compiler to generate the shortest CLFLUSH of 3 bytes with register indirect addressing for the operand, then stomping over those 3 bytes with the alternatives would be the fastest solution. If, of course, three NOPs which get discarded in the front end are cheaper than the near JMP from static_cpu_has. -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. --