Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752797AbeADLD6 (ORCPT + 1 other); Thu, 4 Jan 2018 06:03:58 -0500 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:38178 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752605AbeADLD5 (ORCPT ); Thu, 4 Jan 2018 06:03:57 -0500 Date: Thu, 4 Jan 2018 12:03:51 +0100 From: Willy Tarreau To: Andres Freund Cc: Linus Torvalds , Linux Kernel Mailing List Subject: Re: Linux 4.15-rc6 Message-ID: <20180104110351.GC3235@1wt.eu> References: <20180102202859.4fvvrtngnitwzfym@alap3.anarazel.de> <20180103125724.GA2189@1wt.eu> <20180103212000.zvll6xvgj3idysgd@alap3.anarazel.de> <20180104102704.GB3235@1wt.eu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180104102704.GB3235@1wt.eu> 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 Thu, Jan 04, 2018 at 11:27:04AM +0100, Willy Tarreau wrote: > > The post linked above has numbers with nopcid disabling pcid use, and > > indeed, the difference is quite measurable. > > I'm going to re-run the tests on an Atom C2518 now, which doesn't have pcid, > I don't even know if it's affected by the issue. FWIW the performance loss on the Atom is less important (probably in part because other parts are slower and bottlenecks are spread in all the hardware). I'm observing "only" 11-14% loss on the same tests. Willy