From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751377AbcFFGYY (ORCPT ); Mon, 6 Jun 2016 02:24:24 -0400 Received: from nbd.name ([46.4.11.11]:43430 "EHLO nbd.name" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751130AbcFFGYX (ORCPT ); Mon, 6 Jun 2016 02:24:23 -0400 Subject: Re: [PATCH 09/12] net: mediatek: increase watchdog_timeo To: Andrew Lunn References: <1465108385-38286-1-git-send-email-john@phrozen.org> <1465108385-38286-10-git-send-email-john@phrozen.org> <20160605145632.GI12165@lunn.ch> Cc: Sean Wang , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mediatek@lists.infradead.org, "David S. Miller" , Felix Fietkau From: John Crispin Message-ID: <0da64a49-d100-f83d-e6d3-91b706710660@phrozen.org> Date: Mon, 6 Jun 2016 08:24:08 +0200 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 MIME-Version: 1.0 In-Reply-To: <20160605145632.GI12165@lunn.ch> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/06/2016 16:56, Andrew Lunn wrote: > On Sun, Jun 05, 2016 at 08:33:02AM +0200, John Crispin wrote: >> During stress testing, after reducing the threshold value, we have seen >> TX timeouts that were caused by the watchdog_timeo value being too low. >> Increase the value to 5 * HZ which is a value commonly used by many other >> drivers. > > I've never studied what watchdog_timeo actually means. Does it mean a > transmit has not completed in that amount of time? Would this imply > you have 5 seconds worth of packets in your transmit queue? Do you > know what the driver is doing during this 5 seconds? Hi Andrew, it is waiting for the watchdog to trigger :-) TBH the 1s seems to be too short to for the dma ring length to be flushed and i had to pick some value and 5 is used most places. it really depends on the amount of packets in the queue, their length and the mac setting. the timeout needs to be large enough that it would not trigger incorrectly even if the mac is on 10mbit half duplex and all frames in the queue were maximum size. John