From mboxrd@z Thu Jan 1 00:00:00 1970 From: santosh Subject: Re: [PATCH v4 2/2] ethdev: get the supported pools for a port Date: Fri, 29 Sep 2017 11:16:20 +0100 Message-ID: References: <20170815080717.9413-1-santosh.shukla@caviumnetworks.com> <20170911151837.25092-1-santosh.shukla@caviumnetworks.com> <20170911151837.25092-3-santosh.shukla@caviumnetworks.com> <20170925073728.auchwn7mxx63b32j@platinum> <8b832367-e8fa-077a-1732-50627e977f9c@caviumnetworks.com> <20170929083242.a4arzpf2drfqyxpj@platinum> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: dev@dpdk.org, thomas@monjalon.net, jerin.jacob@caviumnetworks.com, hemant.agrawal@nxp.com To: Olivier MATZ Return-path: Received: from NAM01-SN1-obe.outbound.protection.outlook.com (mail-sn1nam01on0057.outbound.protection.outlook.com [104.47.32.57]) by dpdk.org (Postfix) with ESMTP id 531671B22C for ; Fri, 29 Sep 2017 12:16:27 +0200 (CEST) In-Reply-To: <20170929083242.a4arzpf2drfqyxpj@platinum> List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Hi Olivier, On Friday 29 September 2017 09:32 AM, Olivier MATZ wrote: > On Mon, Sep 25, 2017 at 10:52:31PM +0100, santosh wrote: >> Hi Olivier, >> >> >> On Monday 25 September 2017 08:37 AM, Olivier MATZ wrote: >> >>>> +{ >>>> + struct rte_eth_dev *dev; >>>> + const char *tmp; >>>> + >>>> + RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV); >>>> + >>>> + if (pool == NULL) >>>> + return -EINVAL; >>>> + >>>> + dev = &rte_eth_devices[port_id]; >>>> + >>>> + if (*dev->dev_ops->pools_ops_supported == NULL) { >>>> + tmp = rte_eal_mbuf_default_mempool_ops(); >>>> + if (!strcmp(tmp, pool)) >>>> + return 0; >>>> + else >>>> + return -ENOTSUP; >>> I don't understand why we are comparing with >>> rte_eal_mbuf_default_mempool_ops(). >>> >>> It means that the result of the function would be influenced >>> by the parameter given by the user. >> But that will be only for ops not supported case and in that case, >> function _must_ make sure that if inputted param is _default_ops_name >> then function should return ops supported correct info (whether >> returning '0' : Best ops or '1': ops does support >> , this part is arguable.. meaning One can say that default_ops ='handle-name' is best possible handle Or >> one of handle which platform supports). >> >>> I think that a PMD that does not implement ->pools_ops_supported >>> should always return 1 (mempool is supported). > I don't agree. > The result of this API (mempool ops supported or not by a PMD) > should not depend on what user asks for. > >> Return 1 says: PMD support this ops.. >> >> So if ops is not supported and func returns with 1, then which ops application will use? >> If that ops is default_ops.. then How application will distinguish when to use default ops or >> param ops?.. as because in both cases func will return with value 1. >> >> The approach in the patch takes care of that condition and func will return -ENOTSUP >> if (ops not support || inputted param not matching with default ops) otherwise will return >> 0 or 1. >> >> At application side; >> For error case: In case of -ENOTSUP, its upto application to use _default_ops or exit. >> For good case: 0 or 1 case, func gaurantee that handle is either best handle for pool or pool supports >> that handle.. However in your suggestion if ops not supported case returns 1 then application is not >> sure which ops to use.. default_ops Or input ops given to func. >> >> make sense? > My proposition is: > > - what a PMD returns does not depend on used parameter: > - 0: best support > - 1: support > - -ENOTSUP: not supported > > - if a PMD does not implement the _ops_supported() API, assume all pools > are supported (returns 1) If API returns 1 for PMD does not implement _ops_supported() case, then do we really need -ENOTSUP? If so then in which case API will return -ENOTSUP error, wondering. > - if the user does not pass a specific mempool ops, the application asks > the PMDs, finds the best mempool ops, and use it. This could even be > done in rte_pktmbuf_pool_create() as discussed at the summit. Right. > - if the user passes a specific mempool ops, we don't need to call the > _ops_supported() api, we just try to use this pool. > > > The _ops_supported() returns a property of a PMD, in my opinion it > should not be impacted by a user argument. > Thanks.