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=-9.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT 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 7B050C43387 for ; Thu, 17 Jan 2019 15:41:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 45F2E20851 for ; Thu, 17 Jan 2019 15:41:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547739716; bh=Xz9fQIXuQQe0UnxUxNP5rtYpGmjpTeJVtfMuT9DisNU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=PbottBQVZdUjt7V89ZMy55tX/YPpEPxJ7W69HxiVGsiSi5vhkdUMdlMtwNWWyq5Aj 2vjHC9FDd7p8zitKdwGdJQjW/wxtwECHN9LFW9hLFC48KpaopkD1ILqfUH1wpI189U amKLuPR5AlUY8N8pPH6xXrppaQQ61FLbPYj8Li6Q= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728013AbfAQPlz (ORCPT ); Thu, 17 Jan 2019 10:41:55 -0500 Received: from mail.kernel.org ([198.145.29.99]:42646 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726162AbfAQPly (ORCPT ); Thu, 17 Jan 2019 10:41:54 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7567D20851; Thu, 17 Jan 2019 15:41:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547739714; bh=Xz9fQIXuQQe0UnxUxNP5rtYpGmjpTeJVtfMuT9DisNU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jV/HD/VTkFO8yqR4QhbjbJfPBlKvv0+WyGTTJB+6gPURuau+owKtGA8r2HXyZZPXE +V36JRrmT852/p+dkcJvyGPc5eiAbmdINq/j3Cuavbm39c6oMUOfDVh0FmGqwf2/9k ej0cZW+dihOnrc2EKwp1yXQZbeW7+oyfy3b1EZGA= Date: Thu, 17 Jan 2019 16:41:51 +0100 From: Greg Kroah-Hartman To: "Rafael J. Wysocki" Cc: Keith Busch , Linux Kernel Mailing List , ACPI Devel Maling List , Linux Memory Management List , Dave Hansen , Dan Williams Subject: Re: [PATCHv4 07/13] node: Add heterogenous memory access attributes Message-ID: <20190117154151.GA3970@kroah.com> References: <20190116175804.30196-1-keith.busch@intel.com> <20190116175804.30196-8-keith.busch@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.2 (2019-01-07) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 17, 2019 at 04:03:42PM +0100, Rafael J. Wysocki wrote: > On Wed, Jan 16, 2019 at 6:59 PM Keith Busch wrote: > > > > Heterogeneous memory systems provide memory nodes with different latency > > and bandwidth performance attributes. Provide a new kernel interface for > > subsystems to register the attributes under the memory target node's > > initiator access class. If the system provides this information, applications > > may query these attributes when deciding which node to request memory. > > > > The following example shows the new sysfs hierarchy for a node exporting > > performance attributes: > > > > # tree -P "read*|write*" /sys/devices/system/node/nodeY/classZ/ > > /sys/devices/system/node/nodeY/classZ/ > > |-- read_bandwidth > > |-- read_latency > > |-- write_bandwidth > > `-- write_latency > > > > The bandwidth is exported as MB/s and latency is reported in nanoseconds. > > Memory accesses from an initiator node that is not one of the memory's > > class "Z" initiator nodes may encounter different performance than > > reported here. When a subsystem makes use of this interface, initiators > > of a lower class number, "Z", have better performance relative to higher > > class numbers. When provided, class 0 is the highest performing access > > class. > > > > Signed-off-by: Keith Busch > > --- > > drivers/base/Kconfig | 8 ++++++++ > > drivers/base/node.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ > > include/linux/node.h | 25 +++++++++++++++++++++++++ > > 3 files changed, 81 insertions(+) > > > > diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig > > index 3e63a900b330..6014980238e8 100644 > > --- a/drivers/base/Kconfig > > +++ b/drivers/base/Kconfig > > @@ -149,6 +149,14 @@ config DEBUG_TEST_DRIVER_REMOVE > > unusable. You should say N here unless you are explicitly looking to > > test this functionality. > > > > +config HMEM_REPORTING > > + bool > > + default y default y is only if the machine will not boot without it. Please never make a new option y unless you really really have to have it on all machines in the world. Hint, not here. greg k-h