From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8CF93C7618B for ; Tue, 23 Jul 2019 14:09:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5FD1021842 for ; Tue, 23 Jul 2019 14:09:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="0+NQ0ipb" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390454AbfGWOJX (ORCPT ); Tue, 23 Jul 2019 10:09:23 -0400 Received: from merlin.infradead.org ([205.233.59.134]:44556 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726201AbfGWOJV (ORCPT ); Tue, 23 Jul 2019 10:09:21 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=0cYM+DTV87A8Im7WmiAo3ahAlUZLht+ioCM/P9jm3xs=; b=0+NQ0ipbp40HPoN0bwsD2IYm7 TfJzAW4ifIJutuHCj6ueh2ldmzZ2/b4fFjh9Rty4XUAJdKZOhbBSSfXc6vuslcM3pv9jCc3m5JT2K Vy4g0XeRl5LpHOoRHY3+3nUFth7JciMPKdQuve2eQ4nA/EoTdcX5ULyz9/HZ01mB8rcA1Sc7Nj1DW c8rBo7GW97AHCT03RP7HZPWZminaufXvmV/BPldP0NxR3NdHKRmz+uQwt3XWhDO/9tCpfkKfb/bnj HqZOnp7k5hDi9CCP5P3ciVZ2+8LBnPIJbDqVD4/mzxP/efxhqfIBQlPrS8J5IgH11MI6te7Ehoms6 6l8oJv2MA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1hpvTY-0008UM-66; Tue, 23 Jul 2019 14:09:08 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id A2636201A93DD; Tue, 23 Jul 2019 16:09:05 +0200 (CEST) Date: Tue, 23 Jul 2019 16:09:05 +0200 From: Peter Zijlstra To: Mel Gorman Cc: Matt Fleming , linux-kernel@vger.kernel.org, "Suthikulpanit, Suravee" , "Lendacky, Thomas" , Borislav Petkov Subject: Re: [PATCH v3] sched/topology: Improve load balancing on AMD EPYC Message-ID: <20190723140905.GF3402@hirez.programming.kicks-ass.net> References: <20190723104830.26623-1-matt@codeblueprint.co.uk> <20190723114248.GJ24383@techsingularity.net> <20190723120030.GN3419@hirez.programming.kicks-ass.net> <20190723130321.GK24383@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190723130321.GK24383@techsingularity.net> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 23, 2019 at 02:03:21PM +0100, Mel Gorman wrote: > On Tue, Jul 23, 2019 at 02:00:30PM +0200, Peter Zijlstra wrote: > > On Tue, Jul 23, 2019 at 12:42:48PM +0100, Mel Gorman wrote: > > > On Tue, Jul 23, 2019 at 11:48:30AM +0100, Matt Fleming wrote: > > > > Signed-off-by: Matt Fleming > > > > Cc: "Suthikulpanit, Suravee" > > > > Cc: Mel Gorman > > > > Cc: "Lendacky, Thomas" > > > > Cc: Borislav Petkov > > > > > > Acked-by: Mel Gorman > > > > > > The only caveat I can think of is that a future generation of Zen might > > > take a different magic number than 32 as their remote distance. If or > > > when this happens, it'll need additional smarts but lacking a crystal > > > ball, we can cross that bridge when we come to it. > > > > I just suggested to Matt on IRC we could do something along these lines, > > but we can do that later. > > > > That would seem fair but I do think it's something that could be done > later (maybe 1 release away?) to avoid a false bisection to this patch by > accident. Quite agreed; changing reclaim_distance like that will affect a lot of hardware, while the current patch limits the impact to just AMD-Zen based bits. > I don't *think* there are any machines out there with a 1-hop > distance of 14 but if there is, your patch would make a difference to > MM behaviour. In the same context, it might make sense to rename the > value to somewhat reflective of the fact that "reclaim distance" affects > scheduler placement. No good name springs to mind at the moment. Yeah, naming sucks. Let us pain this bicycle shed blue!