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=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 87676C433E0 for ; Tue, 14 Jul 2020 16:29:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 57F97223AB for ; Tue, 14 Jul 2020 16:29:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594744147; bh=4odRCreeBpRWf9k9xWiKzOUUUo8g02gshG5+keJQUpI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=mP9tn0yx4WtwLwcoP5YZ3uDlu8VR2mcfzm+F1rFTo1Veb0Mv6rhez32IGCvcR+p2x k4yaR0m3sUhEhJ0uybeYYjWRFGor59bfNIxLiLmUW376VADHpiKsy9+XW1Kosv4/S4 rY2zcQBHAOY3B9runqE2AdvxRVgVUKpwTTCDuLh0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728721AbgGNQ3F (ORCPT ); Tue, 14 Jul 2020 12:29:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:52692 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725890AbgGNQ3F (ORCPT ); Tue, 14 Jul 2020 12:29:05 -0400 Received: from kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com (unknown [163.114.132.1]) (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 B70D8223AB; Tue, 14 Jul 2020 16:29:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594744145; bh=4odRCreeBpRWf9k9xWiKzOUUUo8g02gshG5+keJQUpI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=SsC/k4KH0RiKnJyANHzdOQq2xkfSIzMcUbenVPrxpqUdLls+fCuP/Te4F3n2mT6ES Ksiq2dUy9HseBQclYz3xZf23DYiDtkE3PciLBNK4A248cYbmVaCAc4KLQ/LyYNx6o1 tOvT3MOvsF7BlEZ4t/IRK7luPGIQAsZR1fodbsXo= Date: Tue, 14 Jul 2020 09:29:03 -0700 From: Jakub Kicinski To: "Westergreen, Dalon" Cc: "Ooi, Joyce" , "See, Chin Liang" , "linux-kernel@vger.kernel.org" , "Nguyen, Dinh" , "davem@davemloft.net" , "thor.thayer@linux.intel.com" , "Tan, Ley Foon" , "netdev@vger.kernel.org" , Michal Kubecek Subject: Re: [PATCH v4 09/10] net: eth: altera: add msgdma prefetcher Message-ID: <20200714092903.38581b74@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> In-Reply-To: <3bcb9020f0a3836f41036ddc3c8034b96e183197.camel@intel.com> References: <20200708072401.169150-1-joyce.ooi@intel.com> <20200708072401.169150-10-joyce.ooi@intel.com> <20200708144900.058a8b25@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <20200714085526.2bb89dc6@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <3bcb9020f0a3836f41036ddc3c8034b96e183197.camel@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 14 Jul 2020 15:58:53 +0000 Westergreen, Dalon wrote: > On Tue, 2020-07-14 at 08:55 -0700, Jakub Kicinski wrote: > > On Tue, 14 Jul 2020 14:35:16 +0000 Ooi, Joyce wrote: > > > > I'm no device tree expert but these look like config options rather than > > > > HW > > > > description. They also don't appear to be documented in the next patch. > > > > > > The poll_freq are part of the msgdma prefetcher IP, whereby it > > > specifies the frequency of descriptor polling operation. I can add > > > the poll_freq description in the next patch. > > > > Is the value decided at the time of synthesis or can the driver choose > > the value it wants? > > It is not controlled at synthesis, this parameter should likely not be a > devicetree parameter, perhaps just make it a module parameter with a default > value. Let's see if I understand the feature - instead of using a doorbell the HW periodically checks the contents of the next-to-use descriptor to see if it contains a valid tx frame or rx buffer? I've seen vendors abuse fields of ethtool --coalesce to configure similar settings. tx-usecs-irq and rx-usecs-irq, I think. Since this part of ethtool API has been ported to netlink, could we perhaps add a new field to ethtool --coalesce?