From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757244AbcDHKjp (ORCPT ); Fri, 8 Apr 2016 06:39:45 -0400 Received: from mail.skyhub.de ([78.46.96.112]:44688 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751957AbcDHKjo (ORCPT ); Fri, 8 Apr 2016 06:39:44 -0400 Date: Fri, 8 Apr 2016 12:39:39 +0200 From: Borislav Petkov To: Andy Lutomirski Cc: security@kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, Linus Torvalds , Rudolf Marek Subject: Re: [PATCH v3 0/7] x86: Pile o' FS/GS changes Message-ID: <20160408103939.GE29522@pd.tnic> References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 07, 2016 at 05:31:43PM -0700, Andy Lutomirski wrote: > Hi all- > > This whole mess is intended for x86/urgent. It fixes several bugs. > > It's probably a tiny performance regression on some workloads on > Intel CPUs. It's probably varies between a less tiny regression and > a small speedup on newer AMD CPUs. It's a bigger regression on AMD > K8. Shhh, otherwise the 2-3 K8 users left would crawl out of the woodwork complaining. ;-) > The AMD code could be further sped up by adding a new 'clear_gs' > pvop with a better native implementation. I don't particularly want > to deal with a backported new pvop, so I didn't do that. Maybe I'll > do it later on for new kernels, though. Yeah, before you do that, we should probably measure that first to see whether it is worth the trouble and the added pvop gunk at all. -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply.