From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: [net 2/6] igb: Fix the transmission mode of queue 0 for Qav mode Date: Wed, 25 Apr 2018 12:27:30 +0300 Message-ID: <429fd25c-7fff-6c3b-098f-be0e4f94bdd5@cogentembedded.com> References: <20180424192911.22786-1-jeffrey.t.kirsher@intel.com> <20180424192911.22786-3-jeffrey.t.kirsher@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Vinicius Costa Gomes , netdev@vger.kernel.org, nhorman@redhat.com, sassmann@redhat.com, jogreene@redhat.com To: Jeff Kirsher , davem@davemloft.net Return-path: Received: from mail-lf0-f41.google.com ([209.85.215.41]:38481 "EHLO mail-lf0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751419AbeDYJ1c (ORCPT ); Wed, 25 Apr 2018 05:27:32 -0400 Received: by mail-lf0-f41.google.com with SMTP id z130-v6so24452988lff.5 for ; Wed, 25 Apr 2018 02:27:32 -0700 (PDT) In-Reply-To: <20180424192911.22786-3-jeffrey.t.kirsher@intel.com> Content-Language: en-US Sender: netdev-owner@vger.kernel.org List-ID: On 4/24/2018 10:29 PM, Jeff Kirsher wrote: > From: Vinicius Costa Gomes > > When Qav mode is enabled, queue 0 should be kept on Stream Reservation s/on/in/? > mode. From the i210 datasheet, section 8.12.19: > > "Note: Queue0 QueueMode must be set to 1b when TransmitMode is set to > Qav." ("QueueMode 1b" represents the Stream Reservation mode) > > The solution is to give queue 0 the all the credits it might need, so > it has priority over queue 1. > > A situation where this can happen is when cbs is "installed" only on > queue 1, leaving queue 0 alone. For example: > > $ tc qdisc replace dev enp2s0 handle 100: parent root mqprio num_tc 3 \ > map 2 2 1 0 2 2 2 2 2 2 2 2 2 2 2 2 queues 1@0 1@1 2@2 hw 0 > > $ tc qdisc replace dev enp2s0 parent 100:2 cbs locredit -1470 \ > hicredit 30 sendslope -980000 idleslope 20000 offload 1 > > Signed-off-by: Vinicius Costa Gomes > Tested-by: Aaron Brown > Signed-off-by: Jeff Kirsher [...] MBR, Sergei