From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757307AbeAHUj3 (ORCPT + 1 other); Mon, 8 Jan 2018 15:39:29 -0500 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:39009 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757045AbeAHUj0 (ORCPT ); Mon, 8 Jan 2018 15:39:26 -0500 Date: Mon, 8 Jan 2018 21:39:20 +0100 From: Willy Tarreau To: Yves-Alexis Perez Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: Feedback on 4.9 performance after PTI fixes Message-ID: <20180108203920.GB11238@1wt.eu> References: <20180107101856.GA9590@1wt.eu> <1515431274.3305.59.camel@debian.org> <20180108182622.GM10913@1wt.eu> <1515443170.3305.73.camel@debian.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1515443170.3305.73.camel@debian.org> User-Agent: Mutt/1.6.1 (2016-04-27) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On Mon, Jan 08, 2018 at 09:26:10PM +0100, Yves-Alexis Perez wrote: > On Mon, 2018-01-08 at 19:26 +0100, Willy Tarreau wrote: > > You're totally right, I discovered during my later developments that > > indeed PCID is not exposed there. So we take the hit of a full TLB > > flush twice per syscall. > > So I really think it might make sense to redo the tests with PCID, because the > assumptions you're basing your patch series on might actually not hold. I'll have to do it on the bare-metal server soon anyway. Cheers, Willy