From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vadim Pasternak Subject: RE: [PATCH v0 03/12] mlxsw: core: Add core environment module for port temperature reading Date: Thu, 21 Jun 2018 18:14:43 +0000 Message-ID: References: <1529594883-20619-1-git-send-email-vadimp@mellanox.com> <1529594883-20619-4-git-send-email-vadimp@mellanox.com> <20180621171120.GA6830@lunn.ch> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Cc: "davem@davemloft.net" , "netdev@vger.kernel.org" , "jiri@resnulli.us" To: Andrew Lunn Return-path: Received: from mail-eopbgr70041.outbound.protection.outlook.com ([40.107.7.41]:13997 "EHLO EUR04-HE1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932620AbeFUSOr (ORCPT ); Thu, 21 Jun 2018 14:14:47 -0400 In-Reply-To: <20180621171120.GA6830@lunn.ch> Content-Language: en-US Sender: netdev-owner@vger.kernel.org List-ID: > -----Original Message----- > From: Andrew Lunn [mailto:andrew@lunn.ch] > Sent: Thursday, June 21, 2018 8:11 PM > To: Vadim Pasternak > Cc: davem@davemloft.net; netdev@vger.kernel.org; jiri@resnulli.us > Subject: Re: [PATCH v0 03/12] mlxsw: core: Add core environment module fo= r > port temperature reading >=20 > > New internal API reads the temperature from all the modules, which are > > equipped with the thermal sensor and exposes temperature according to > > the worst measure. All individual temperature values are normalized to > > pre-defined range. >=20 > Hi Vadim >=20 > Could you explain this normalization process. Why are you not just expose= each > sensors temperature in millidegrees C, which is the normal for HWMON. Hi Andrew, The temperature of each individual module can be obtained through ethtool. The worst temperature is necessary for the system cooling control decision. Up to 64 SFP/QSFP modules could be connected to the system. Some of them could cooper modules, which doesn't provide temperature measurement. Some of them could be optical modules, providing untrusted temperature measurement, which could impact thermal control of the system. Also optical modules could be from the different vendors, and this is real situation, when, f.e. one module has the warning and critical thresholds 75C and 85C, while another 70C and 80C. In such case the first module temperature 72C is better, then the second module temperature 71C. And deltas between warning and critical thresholds, could be different as well. It could be 5C, 10C, etc. =20 So, nominal temperature is not the case here, we should know the "worst" value for the thermal control decision. Thanks, Vadim. >=20 > Andrew