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 DE0B042A4B; Wed, 3 May 2023 09:58:33 +0200 (CEST) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 792C34114B; Wed, 3 May 2023 09:58:33 +0200 (CEST) Received: from mail-vk1-f169.google.com (mail-vk1-f169.google.com [209.85.221.169]) by mails.dpdk.org (Postfix) with ESMTP id 546D541144 for ; Wed, 3 May 2023 09:58:31 +0200 (CEST) Received: by mail-vk1-f169.google.com with SMTP id 71dfb90a1353d-44f985f250aso157374e0c.3 for ; Wed, 03 May 2023 00:58:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1683100710; x=1685692710; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=yRQ8hnUYVg+rrEaOFQaKi/AV/1rKjI5obrMDzkRcUnw=; b=P83SdTJpLNn4CkL1xUrbdqIKQ3rnzHp9od97wpZb+7aewVWctMBpNorQSMF42/ctKC JGUJAZSgvIjY01Uk7yYrBjicbel8CThDnlD2O4mbksC4xag+Sxzvy/m3ycNPDxYlCRkd sjHV7N+HlQHeHxf9EmlikleTv1MJ1EYyP7ApjrFACUcyxl3cFKG8CqlAviu8ZEFIiIBJ nPWaC6GLXL1dJxqhQ2hzUnhku6t5/KhXoN0qypqe7a3UQWN5KaCHHsH9NOmJwYvBtWyK uXqYsDNvCk325nwFFqOAKoGnV8ZnUv7l5zAbXY151E55DpMQOFhrf30x6IYlKwqIuYCY kAfw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683100710; x=1685692710; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=yRQ8hnUYVg+rrEaOFQaKi/AV/1rKjI5obrMDzkRcUnw=; b=A5gyWxO9mvK0ZvY5R5SRJiHaJKj1Q62DtgIsrs6dg0CRGApFWtVXJRgAV9X9KJz4mM Mj9O7ixPspwUVCNiemt6sdJzLmOkOuNIolBKvP+/HmJ7chz8YsE+t7KiiRfeUGVnTP4F hfBoJjqBLe9ZMPqpA/HG/yzXAqBTO+ZZeZH+BaeGeFLxbNz1mv2+CspxxtfCFE62A5Tx 8K/EqMsKBp9LkfMu5CCGAAegBqiAVD4Ek+W6x7pjTLw0bOG7kbU+0y/F2OoRYzpKtbhB V9yMXMZ+Ck2TzpecOgWaiZJme3zLXjeNjIIvuEEine4J5jy7ZvcvFV8lvudXz8DUtiXc fjEQ== X-Gm-Message-State: AC+VfDyZLI+HYvZSg/ES6vhTLUSVFFKJzh/6GUfKZZuOvlYqMzVrr0SA 8Va/GdDNIH56tW4A9GkcXBWh7Yar7rbAg2EyP2k= X-Google-Smtp-Source: ACHHUZ512y+c8f7ESF/BTUYggshOto0jHv34sLeCUKceZBT52mxf5Px9Hq2O00xEsYsWWasXv6b28UMtjSJ1FU/tmfU= X-Received: by 2002:a1f:bf55:0:b0:43f:c4b2:b11d with SMTP id p82-20020a1fbf55000000b0043fc4b2b11dmr6821299vkf.3.1683100710526; Wed, 03 May 2023 00:58:30 -0700 (PDT) MIME-Version: 1.0 References: <20230419095427.563185-1-sivaprasad.tummala@amd.com> <324d5201-da95-f926-5580-f74ca5c09799@amd.com> In-Reply-To: From: Jerin Jacob Date: Wed, 3 May 2023 13:28:04 +0530 Message-ID: Subject: Re: [RFC PATCH 1/5] eventdev: add power monitoring API on event port To: Ferruh Yigit Cc: Sivaprasad Tummala , david.hunt@intel.com, jerinj@marvell.com, harry.van.haaren@intel.com, dev@dpdk.org, Pavan Nikhilesh , "McDaniel, Timothy" , Shijith Thotton , Hemant Agrawal , Sachin Saxena , =?UTF-8?Q?Mattias_R=C3=B6nnblom?= , Peter Mccarthy , Liang Ma Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable 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 Tue, May 2, 2023 at 4:49=E2=80=AFPM Ferruh Yigit = wrote: > > On 4/25/2023 5:09 AM, Jerin Jacob wrote: > > On Mon, Apr 24, 2023 at 9:36=E2=80=AFPM Ferruh Yigit wrote: > >> > >> On 4/19/2023 11:15 AM, Jerin Jacob wrote: > >>> On Wed, Apr 19, 2023 at 3:24=E2=80=AFPM Sivaprasad Tummala > >>> wrote: > >>>> > >>>> A new API to allow power monitoring condition on event port to > >>>> optimize power when no events are arriving on an event port for > >>>> the worker core to process in an eventdev based pipelined applicatio= n. > >>>> > >>>> Signed-off-by: Sivaprasad Tummala > >>>> + * > >>>> + * @param dev_id > >>>> + * Eventdev id > >>>> + * @param port_id > >>>> + * Eventdev port id > >>>> + * @param pmc > >>>> + * The pointer to power-optimized monitoring condition structure. > >>>> + * > >>>> + * @return > >>>> + * - 0: Success. > >>>> + * -ENOTSUP: Operation not supported. > >>>> + * -EINVAL: Invalid parameters. > >>>> + * -ENODEV: Invalid device ID. > >>>> + */ > >>>> +__rte_experimental > >>>> +int > >>>> +rte_event_port_get_monitor_addr(uint8_t dev_id, uint8_t port_id, > >>>> + struct rte_power_monitor_cond *pmc); > >>> > >>> + eventdev driver maintainers > >>> > >>> I think, we don't need to expose this application due to applications > >>> 1)To make applications to be transparent whether power saving is enab= led or not? > >>> 2)Some HW and Arch already supports power managent in driver and in H= W > >>> (Not using CPU architecture directly) > >>> > >>> If so, that will be translated to following, > >>> a) Add rte_event_port_power_saving_ena_dis(uint8_t dev_id, uint8_t > >>> port_id, bool ena) for controlling power saving in slowpath. > >>> b) Create reusable PMD private function based on the CPU architecture > >>> power saving primitive to cover the PMD don't have native power savin= g > >>> support. > >>> c)Update rte_event_dequeue_burst() burst of PMD callback to use (b). > >>> > >>> > >> > >> Hi Jerin, > > > > Hi Ferruh, > > > >> > >> ethdev approach seems applied here. > > > > Understands that. But none of the NIC HW supports power management at > > HW level like eventdev, so that way > > for what we are doing for ethdev is a correct abstraction for ethdev. > > > > What I understand is there is HW based event manager and SW based ones, > SW based ones can benefit more from CPU power optimizations, for HW > event managers if there is not enough benefit they can just ignore the > feature. > > >> > >> In ethdev, 'rte_event_port_get_monitor_addr()' equivalent is > >> 'rte_eth_get_monitor_addr()'. > >> > >> Although 'rte_eth_get_monitor_addr()' is public API, it is currently > >> only called from Rx/Tx callback functions implemented in the power lib= rary. > >> But I assume intention to make it public is to enable users to impleme= nt > >> their own callback functions that has custom algorithm for the power > >> management. > > > > If there is a use case for customizing with own callback, we can provid= e that. > > Provided NULL is valid with default algorithm. > > > >> > >> And probably same is true for the 'rte_event_port_get_monitor_addr()'. > >> > >> > >> Also instead of implementing power features for withing PMDs, isn't it > >> better to have a common eventdev layer for it? > > > > We can have rte_evetdev_pmd_* APIs as non-public APIs. > > My only objection is to NOT introduce _monitor_ APIs at eventdev level, > > Instead, _monitor_ is one way to do it in SW, So we need higher level > > of abstraction. > > > > I see, this seems a trade off between flexibility and usability. If > application has access to _monitor_ APIs, they can be more flexible to > implement their own logic. OK. > > Another option can be application provides the policy with an API and > monitor API used to realize the policy, but for this case it can be > challenge to find and implement correct policies. OK. If we can enumerate the policies, then it will be ideal. On plus side, there will not be any changes in needed in lib/power/ > > >> > >> For the PMDs benefit from HW event manager, just not implementing > >> .get_monitor_addr() dev_ops will make them free from power related API= s. > > > > But application fast path code gets diverged by exposing low level prim= itives. > > > > I am not clear with concern above, but for application that use default > callbacks, 'rte_power_eventdev_pmgmt_port_enable()' needs to be called > to enable this feature, if not called datapath is not impacted. > And if not dequeue callback added at all, custom or default, data path > is not impacted at all. Concerns are around following code[1] when callback is not registered for this use case. In eventdev, we are using _one packet at a time_ for a lot of use case with latency critical workload like L1 processing. On such cases, the following code will add up. [1] cb =3D __atomic_load_n((void **)&fp_ops->ev_port.clbk[port_id], __ATOMIC_RELAXED); if (unlikely(cb !=3D NULL)) nb_rx =3D rte_event_dequeue_callbacks(dev_id, port_id, ev, nb_rx, cb= ); I see two options, 1) Enumerate the power policy and let driver implement through non-public PMD helper functions OR 2)Move the power management callback to driver via non-public PMD helper functions to avoid cost of PMDs where power managment done in HW and to remove above extra check when NO callback is registered[1] > >