From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 302E243709; Sat, 16 Dec 2023 10:03:43 +0100 (CET) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id B4F9F402AA; Sat, 16 Dec 2023 10:03:42 +0100 (CET) Received: from shelob.oktetlabs.ru (shelob.oktetlabs.ru [91.220.146.113]) by mails.dpdk.org (Postfix) with ESMTP id 481E6402A8 for ; Sat, 16 Dec 2023 10:03:41 +0100 (CET) Received: from [192.168.38.17] (aros.oktetlabs.ru [192.168.38.17]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by shelob.oktetlabs.ru (Postfix) with ESMTPSA id 4211C66; Sat, 16 Dec 2023 12:03:40 +0300 (MSK) DKIM-Filter: OpenDKIM Filter v2.11.0 shelob.oktetlabs.ru 4211C66 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=oktetlabs.ru; s=default; t=1702717420; bh=JQH6+uo84OeBqRdeG3tCExTcunkuF+Pyr+n8NA+DrgI=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=v7JJ6mn71+55rHyLz8iyL12ftnItVRiWAhp0SFYVhXHtbyPvyS6VNPyZIn0AXxJn6 UCqrTY2SQGe2xpBJOQRzSKik4F1gWtxzBlkdemwg08g/HpQm5ur5gNpM/drMXR29jD yMtIUo2yAL1HtfayYBe6vmARCaYU9Y2owVNaq8vw= Message-ID: Date: Sat, 16 Dec 2023 12:03:39 +0300 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC] ethdev: introduce entropy calculation Content-Language: en-US To: Thomas Monjalon , Stephen Hemminger , Ori Kam , Ferruh Yigit Cc: "Dumitrescu, Cristian" , Dariusz Sosnowski , "dev@dpdk.org" , Raslan Darawsheh References: <20231210083100.7893-1-orika@nvidia.com> <20231214092609.1b109278@hermes.local> <09acf24d-fc48-44cd-aa4c-9e810bd96f85@amd.com> <7755907.4vTCxPXJkl@thomas> From: Andrew Rybchenko Organization: OKTET Labs In-Reply-To: <7755907.4vTCxPXJkl@thomas> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org On 12/15/23 19:21, Thomas Monjalon wrote: > 15/12/2023 14:44, Ferruh Yigit: >> On 12/14/2023 5:26 PM, Stephen Hemminger wrote: >>> On Thu, 14 Dec 2023 17:18:25 +0000 >>> Ori Kam wrote: >>> >>>>>> Since encap groups number of different 5 tuples together, if HW doesn’t know >>>>>> how to RSS >>>>>> based on the inner application will not be able to get any distribution of >>>>> packets. >>>>>> >>>>>> This value is used to reflect the inner packet on the outer header, so >>>>> distribution >>>>>> will be possible. >>>>>> >>>>>> The main use case is, if application does full offload and implements the encap >>>>> on >>>>>> the RX. >>>>>> For example: >>>>>> Ingress/FDB match on 5 tuple encap send to hairpin / different port in case of >>>>>> switch. >>>>>> >>>>> >>>>> Smart idea! So basically the user is able to get an idea on how good the RSS >>>>> distribution is, correct? >>>>> >>>> >>>> Not exactly, this simply allows the distribution. >>>> Maybe entropy is a bad name, this is the name they use in the protocol, but in reality >>>> this is some hash calculated on the packet header before the encap and set in the encap header. >>>> Using this hash results in entropy for the packets. Which can be used for load balancing. >>>> >>>> Maybe better name would be: >>>> Rte_flow_calc_entropy_hash? >>>> >>>> or maybe rte_flow_calc_encap_hash (I like it less since it looks like we calculate the hash on the encap data and not the inner part) >>>> >>>> what do you think? >>> >>> Entropy has meaning in crypto and random numbers generators that is different from >>> this usage. So entropy is bad name to use. Maybe rte_flow_hash_distribution? >>> >> >> Hi Ori, >> >> Thank you for the description, it is more clear now. >> >> And unless this is specifically defined as 'entropy' in spec, I am too >> for rename. >> >> At least in VXLAN spec, it is mentioned that this field is to "enable a >> level of entropy", but not exactly names it as entropy. > > Exactly my thought about the naming. > Good to see I am not alone thinking this naming is disturbing :) I'd avoid usage of term "entropy" in this patch. It is very confusing.