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 DDA8FA034F; Mon, 11 Oct 2021 19:15:37 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 6D5AE410E8; Mon, 11 Oct 2021 19:15:37 +0200 (CEST) Received: from shelob.oktetlabs.ru (shelob.oktetlabs.ru [91.220.146.113]) by mails.dpdk.org (Postfix) with ESMTP id 6D1A1410DF for ; Mon, 11 Oct 2021 19:15:35 +0200 (CEST) Received: from [192.168.1.192] (unknown [188.242.181.57]) (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 466167F504; Mon, 11 Oct 2021 20:15:34 +0300 (MSK) DKIM-Filter: OpenDKIM Filter v2.11.0 shelob.oktetlabs.ru 466167F504 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=oktetlabs.ru; s=default; t=1633972534; bh=f0hPiofTx1Bc9mP6ZxOqTI5axlDFy8Lcb9g+TgfFw4U=; h=Subject:To:Cc:References:From:Date:In-Reply-To; b=heEKBlHyKKO/6pnb8VwVHYy/Yf9nyPsT9LI8lds1rSDncwgJ9UnX1qM+ty4AL2KdX prK0xXtocN96bB0GlY/dmYYt1RXHAS68i8NAdFD1A7toWPxcQsRH4xry2T0s9Di4Vm jGCtOlMK4ry6287532HpMT4NeiodgX+a5/MkQPwA= To: "Ananyev, Konstantin" , "dev@dpdk.org" Cc: "Li, Xiaoyun" , "anoobj@marvell.com" , "jerinj@marvell.com" , "ndabilpuram@marvell.com" , "adwivedi@marvell.com" , "shepard.siegel@atomicrules.com" , "ed.czeck@atomicrules.com" , "john.miller@atomicrules.com" , "irusskikh@marvell.com" , "ajit.khaparde@broadcom.com" , "somnath.kotur@broadcom.com" , "rahul.lakkireddy@chelsio.com" , "hemant.agrawal@nxp.com" , "sachin.saxena@oss.nxp.com" , "Wang, Haiyue" , "Daley, John" , "hyonkim@cisco.com" , "Zhang, Qi Z" , "Wang, Xiao W" , "humin29@huawei.com" , "yisen.zhuang@huawei.com" , "oulijun@huawei.com" , "Xing, Beilei" , "Wu, Jingjing" , "Yang, Qiming" , "matan@nvidia.com" , "viacheslavo@nvidia.com" , "sthemmin@microsoft.com" , "longli@microsoft.com" , "heinrich.kuhn@corigine.com" , "kirankumark@marvell.com" , "mczekaj@marvell.com" , "jiawenwu@trustnetic.com" , "jianwang@trustnetic.com" , "maxime.coquelin@redhat.com" , "Xia, Chenbo" , "thomas@monjalon.net" , "Yigit, Ferruh" , "mdr@ashroe.eu" , "Jayatheerthan, Jay" References: <20211004135603.20593-1-konstantin.ananyev@intel.com> <20211007112750.25526-1-konstantin.ananyev@intel.com> <20211007112750.25526-3-konstantin.ananyev@intel.com> From: Andrew Rybchenko Message-ID: <05fdac98-194d-94a8-0fa7-197353c27fe0@oktetlabs.ru> Date: Mon, 11 Oct 2021 20:15:33 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [dpdk-dev] [PATCH v5 2/7] ethdev: allocate max space for internal queue array 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 Sender: "dev" On 10/11/21 7:25 PM, Ananyev, Konstantin wrote: > > >>> At queue configure stage always allocate space for maximum possible >>> number (RTE_MAX_QUEUES_PER_PORT) of queue pointers. >>> That will allow 'fast' inline functions (eth_rx_burst, etc.) to refer >>> pointer to internal queue data without extra checking of current number >>> of configured queues. >>> That would help in future to hide rte_eth_dev and related structures. >>> It means that from now on, each ethdev port will always consume: >>> ((2*sizeof(uintptr_t))* RTE_MAX_QUEUES_PER_PORT) >>> bytes of memory for its queue pointers. >>> With RTE_MAX_QUEUES_PER_PORT==1024 (default value) it is 16KB per port. >>> >>> Signed-off-by: Konstantin Ananyev >>> --- >>> lib/ethdev/rte_ethdev.c | 36 +++++++++--------------------------- >>> 1 file changed, 9 insertions(+), 27 deletions(-) >>> >>> diff --git a/lib/ethdev/rte_ethdev.c b/lib/ethdev/rte_ethdev.c >>> index ed37f8871b..c8abda6dd7 100644 >>> --- a/lib/ethdev/rte_ethdev.c >>> +++ b/lib/ethdev/rte_ethdev.c >>> @@ -897,7 +897,8 @@ eth_dev_rx_queue_config(struct rte_eth_dev *dev, uint16_t nb_queues) >>> >>> if (dev->data->rx_queues == NULL && nb_queues != 0) { /* first time configuration */ >>> dev->data->rx_queues = rte_zmalloc("ethdev->rx_queues", >>> - sizeof(dev->data->rx_queues[0]) * nb_queues, >>> + sizeof(dev->data->rx_queues[0]) * >>> + RTE_MAX_QUEUES_PER_PORT, >>> RTE_CACHE_LINE_SIZE); >> >> Looking at it I have few questions: >> 1. Why is nb_queues == 0 case kept as an exception? Yes, >> strictly speaking it is not the problem of the patch, >> DPDK will still segfault (non-debug build) if I >> allocate Tx queues only but call rte_eth_rx_burst(). > > eth_dev_rx_queue_config(.., nb_queues=0) is used in few places to clean-up things. No, as far as I know. For Tx only application (e.g. traffic generator) it is 100% legal to configure with tx_queues=X, rx_queues=0. The same is for Rx only application (e.g. packet capture). > >> After reading the patch description I thought that >> we're trying to address it. > > We do, though I can't see how we can address it in this patch. > Though it is a good idea - I think I can add extra check in eth_dev_fp_ops_setup() > or around and setup RX function pointers only when dev->data->rx_queues != NULL. > Same for TX. You don't need to care about these pointers, if these arrays are always allocated. See (3) below. > >> 2. Why do we need to allocate memory dynamically? >> Can we just make rx_queues an array of appropriate size? > > Pavan already asked same question. > My answer to him: > Yep we can, and yes it will simplify this peace of code. > The main reason I decided no to do this change now - > it will change layout of the_eth_dev_data structure. > In this series I tried to mininize(/avoid) changes in rte_eth_dev and rte_eth_dev_data, > as much as possible to avoid any unforeseen performance and functional impacts. > If we'll manage to make rte_eth_dev and rte_eth_dev_data private we can in future > consider that one and other changes in rte_eth_dev and rte_eth_dev_data layouts > without worrying about ABI breakage Thanks a lot. Makes sense. >> May be wasting 512K unconditionally is too much. >> 3. If wasting 512K is too much, I'd consider to move >> allocation to eth_dev_get(). If > > Don't understand where 512KB came from. 32 port * 1024 queues * 2 types * 8 pointer size if we allocate as in (2) above. > each ethdev port will always consume: > ((2*sizeof(uintptr_t))* RTE_MAX_QUEUES_PER_PORT) > bytes of memory for its queue pointers. > With RTE_MAX_QUEUES_PER_PORT==1024 (default value) it is 16KB per port. IMHO it will be a bit nicer if queue pointers arrays are allocated on device get if size is fixed. It is just a suggestion. If you disagree, feel free to drop it. >>> if (dev->data->rx_queues == NULL) { >>> dev->data->nb_rx_queues = 0; >>> @@ -908,21 +909,11 @@ eth_dev_rx_queue_config(struct rte_eth_dev *dev, uint16_t nb_queues) >>> >>> rxq = dev->data->rx_queues; >>> >>> - for (i = nb_queues; i < old_nb_queues; i++) >>> + for (i = nb_queues; i < old_nb_queues; i++) { >>> (*dev->dev_ops->rx_queue_release)(rxq[i]); >>> - rxq = rte_realloc(rxq, sizeof(rxq[0]) * nb_queues, >>> - RTE_CACHE_LINE_SIZE); >>> - if (rxq == NULL) >>> - return -(ENOMEM); >>> - if (nb_queues > old_nb_queues) { >>> - uint16_t new_qs = nb_queues - old_nb_queues; >>> - >>> - memset(rxq + old_nb_queues, 0, >>> - sizeof(rxq[0]) * new_qs); >>> + rxq[i] = NULL; >> >> It looks like the patch should be rebased on top of >> next-net main because of queue release patches. >> >> [snip]