From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ferruh Yigit Subject: Re: [PATCH v2 1/4] ethdev: add Rx offload outer UDP checksum definition Date: Mon, 8 Oct 2018 13:13:31 +0100 Message-ID: <80a5780a-f66b-ad7c-8327-37644c69efda@intel.com> References: <20180913134707.23698-1-jerin.jacob@caviumnetworks.com> <601d2413-e148-73c4-e7a5-59f09bd02451@intel.com> <20181008082421.GA3554@jerin> <2218090.RkeNvosNi6@xps> <20181008093741.GA11081@jerin> <20181008115524.GB28968@jerin> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: Thomas Monjalon , "Ananyev, Konstantin" , Andrew Rybchenko , "Lu, Wenzhuo" , "Wu, Jingjing" , "Iremonger, Bernard" , "Mcnamara, John" , "Kovacevic, Marko" , Olivier Matz , "dev@dpdk.org" , "shahafs@mellanox.com" , "didier.pallard@6wind.com" To: Jerin Jacob Return-path: Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by dpdk.org (Postfix) with ESMTP id CC70656A3 for ; Mon, 8 Oct 2018 14:13:35 +0200 (CEST) In-Reply-To: <20181008115524.GB28968@jerin> Content-Language: en-US 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 10/8/2018 12:55 PM, Jerin Jacob wrote: > -----Original Message----- >> Date: Mon, 8 Oct 2018 11:53:01 +0100 >> From: Ferruh Yigit >> To: Jerin Jacob , Thomas Monjalon >> >> CC: "Ananyev, Konstantin" , Andrew Rybchenko >> , "Lu, Wenzhuo" , "Wu, >> Jingjing" , "Iremonger, Bernard" >> , "Mcnamara, John" , >> "Kovacevic, Marko" , Olivier Matz >> , "dev@dpdk.org" , >> "shahafs@mellanox.com" , "didier.pallard@6wind.com" >> >> Subject: Re: [dpdk-dev] [PATCH v2 1/4] ethdev: add Rx offload outer UDP >> checksum definition >> User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 >> Thunderbird/52.9.1 >> >> On 10/8/2018 10:37 AM, Jerin Jacob wrote: >>> -----Original Message----- >>>> Date: Mon, 08 Oct 2018 11:04:51 +0200 >>>> From: Thomas Monjalon >>>> To: Jerin Jacob , Ferruh Yigit >>>> , "Ananyev, Konstantin" >>>> >>>> Cc: Andrew Rybchenko , "Lu, Wenzhuo" >>>> , "Wu, Jingjing" , >>>> "Iremonger, Bernard" , "Mcnamara, John" >>>> , "Kovacevic, Marko" , >>>> Olivier Matz , "dev@dpdk.org" , >>>> "shahafs@mellanox.com" , "didier.pallard@6wind.com" >>>> >>>> Subject: Re: [dpdk-dev] [PATCH v2 1/4] ethdev: add Rx offload outer UDP >>>> checksum definition >>>> >>>> 08/10/2018 10:24, Jerin Jacob: >>>>> From: Ferruh Yigit >>>>>> On 10/6/2018 1:18 PM, Ananyev, Konstantin wrote: >>>>>>> From: Jerin Jacob [mailto:jerin.jacob@caviumnetworks.com] >>>>>>>> From: Thomas Monjalon >>>>>>>>> However, we should re-visit the flag PKT_RX_EIP_CKSUM_BAD. >>>>>>>> >>>>>>>> Do we need to block this patch due to the exiting PKT_RX_EIP_CKSUM_BAD >>>>>>>> definition? >>>>>>>> >>>>>>>> I already added the author of the PKT_RX_EIP_CKSUM_BAD flag and ethdev and mbuf >>>>>>>> maintainers in this list. So what else I need make forward progress >>>>>>>> on this patch? >>>>>>>> >>>>>>>> I think, the definition of PKT_RX_EIP_CKSUM_BAD based on HW capability. It >>>>>>>> is safe to assume that ALL HW can support CKSUM BAD if the feature is >>>>>>>> available and hence it is more portable. >>>>>>> >>>>>>> Yes, as I remember PKT_RX_EIP_CKSUM_BAD is based on DEV_RX_OFFLOAD_OUTER_IPV4_CKSUM. >>>>>> >>>>>> Switching to two bit won't reduce the portability, HW supports only reporting >>>>>> CKSUM_BAD can set BAD || UNKNOWN. >>>>> >>>>> UNKNOWN is not a bit. It is represented as 0. It spec has 2 bit, then >>>>> driver need to report GOOD as well. >>>>> >>>>> Same applies for PKT_RX_EL4_CKSUM as well. >>>>> >>>>>> >>>>>> And I think patch is not blocked by PKT_RX_EIP_CKSUM_BAD, it can be changed >>>>>> separately, for this patch question is can we represent PKT_RX_EL4_CKSUM_* with >>>>>> two bits, to have BAD/GOOD/UNKNOWN? >>>> >>>> Yes, exact. >>>> >>>> PKT_RX_EIP_CKSUM_BAD must be left aside. >>>> We should just avoid taking it as a reference. >>>> And we can reconsider its definition later. >>> >>> OK. >>> >>> IMO, Using 2 bit scheme for tunneled checksum has following performance >>> issue from driver side. >>> >>> Driver need to mark the packet as GOOD. All the HW can support >>> detection of BAD. That not necessary mean GOOD in case of tunnel packet, >>> so driver has to detect the packet is tunneled and packet is not BAD >>> then mark GOOD. >> >> Yes UNKNOWN is not a bit, but a state, why don't use it? Why driver has to check >> it is GOOD? > > The application is going to check is it GOOD or not. Not the driver, > Right? My concern was, If application starts dropping the packet instead checking the BAD, if > it checks == !GOOD. Got it, but when 2 bits state introduced, app should check if check == BAD for drop decision, because it is not GOOD || BAD anymore. > >> >> 0x0 => UNKNOWN >> 0x1 => BAD >> 0x2 => GOOD >> 0x3 => ? (invalid perhaps) >> >> HW that supports detecting good packets can set BAD || GOOD state, HW can detect >> only BAD packet can set BAD || UNKNOWN state. >> >> If BAD is not set, there is an ambiguity of state, lets clarify it in lower >> level, if it is UNKNOWN, let application know it is UNKNOWN. > > OK. > > How about the following then? > > /** > * Mask of bits used to determine the status of outer RX L4 checksum. > * - PKT_RX_EL4_CKSUM_UNKNOWN: no information about the outer RX L4 checksum > * - PKT_RX_EL4_CKSUM_BAD: the outer L4 checksum in the packet is wrong > * - PKT_RX_EL4_CKSUM_GOOD: the outer L4 checksum in the packet is valid > * - PKT_RX_EL4_CKSUM_INVALID: invalid outer L4 checksum state. > * > * The detection of PKT_RX_EL4_CKSUM_GOOD shall be based on the given > * HW capability, At minimum, the PMD should support > * PKT_RX_EL4_CKSUM_UNKNOWN and PKT_RX_EL4_CKSUM_BAD states > * if the offload is available. > */ > #define PKT_RX_EL4_CKSUM_MASK ((1ULL << 21) | (1ULL << 22)) > > #define PKT_RX_IP_CKSUM_UNKNOWN 0 > #define PKT_RX_IP_CKSUM_BAD (1ULL << 21) > #define PKT_RX_IP_CKSUM_GOOD (1ULL << 22) > #define PKT_RX_IP_CKSUM_INVALID ((1ULL << 21) | (1ULL << 22)) Looks good to me. > > >