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 4B77CA0093; Wed, 20 Apr 2022 17:48:25 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 3D1D0410FF; Wed, 20 Apr 2022 17:48:25 +0200 (CEST) Received: from shelob.oktetlabs.ru (shelob.oktetlabs.ru [91.220.146.113]) by mails.dpdk.org (Postfix) with ESMTP id 3C739410FF for ; Wed, 20 Apr 2022 17:48:23 +0200 (CEST) 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 79E2286; Wed, 20 Apr 2022 18:48:22 +0300 (MSK) DKIM-Filter: OpenDKIM Filter v2.11.0 shelob.oktetlabs.ru 79E2286 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=oktetlabs.ru; s=default; t=1650469702; bh=7Cs1gfnyISI+3eLdp3hMIbXCO6GBXKgwa7avvlLz1ac=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=czroKJX1l0jDIy+K1dNSWC3LtkkVFwirv8CVeTZsw7OL2KJIASVmu390cNxO5057B OwjT8lI11jwZC7LrjltrHCTCe80WaV3aNAjJ6ObHwZLVobH7vTjJNLjFA3jRrotWcd eE2+F6pRWBOj/9jCG4kwOomkbcFhsdBbuwSiDB28= Message-ID: Date: Wed, 20 Apr 2022 18:48:22 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [v4 1/3] ethdev: introduce protocol type based header split Content-Language: en-US To: "Ding, Xuan" , "Wu, WenxuanX" , "thomas@monjalon.net" , "Li, Xiaoyun" , "Singh, Aman Deep" , "Zhang, Yuying" , "Zhang, Qi Z" Cc: "dev@dpdk.org" , "stephen@networkplumber.org" , "mb@smartsharesystems.com" , "viacheslavo@nvidia.com" , "Yu, Ping" , "Wang, YuanX" , "david.marchand@redhat.com" , Ferruh Yigit References: <20220303060136.36427-1-xuan.ding@intel.com> <20220402104109.472078-1-wenxuanx.wu@intel.com> <20220402104109.472078-2-wenxuanx.wu@intel.com> <253f6a27-0daa-d708-79e6-607228dda044@oktetlabs.ru> From: Andrew Rybchenko Organization: OKTET Labs In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit 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 Hi Xuan, On 4/12/22 19:15, Ding, Xuan wrote: > Hi Andrew, > >> -----Original Message----- >> From: Andrew Rybchenko >> Sent: Thursday, April 7, 2022 6:48 PM >> To: Wu, WenxuanX ; thomas@monjalon.net; Li, >> Xiaoyun ; Singh, Aman Deep >> ; Zhang, Yuying ; >> Zhang, Qi Z >> Cc: dev@dpdk.org; stephen@networkplumber.org; >> mb@smartsharesystems.com; viacheslavo@nvidia.com; Yu, Ping >> ; Ding, Xuan ; Wang, YuanX >> ; david.marchand@redhat.com; Ferruh Yigit >> >> Subject: Re: [v4 1/3] ethdev: introduce protocol type based header split >> >> On 4/2/22 13:41, wenxuanx.wu@intel.com wrote: >>> From: Xuan Ding >>> >>> Header split consists of splitting a received packet into two separate >>> regions based on the packet content. The split happens after the >>> packet header and before the packet payload. Splitting is usually >>> between the packet header that can be posted to a dedicated buffer and >>> the packet payload that can be posted to a different buffer. >>> >>> Currently, Rx buffer split supports length and offset based packet split. >>> Although header split is a subset of buffer split, configuring buffer >>> split based on length is not suitable for NICs that do split based on >>> header protocol types. Because tunneling makes the conversion from >>> length to protocol type impossible. >>> >>> This patch extends the current buffer split to support protocol type >>> and offset based header split. A new proto field is introduced in the >>> rte_eth_rxseg_split structure reserved field to specify header >>> protocol type. With Rx offload flag RTE_ETH_RX_OFFLOAD_HEADER_SPLIT >>> enabled and protocol type configured, PMD will split the ingress >>> packets into two separate regions. Currently, both inner and outer >>> L2/L3/L4 level header split can be supported. >> >> RTE_ETH_RX_OFFLOAD_HEADER_SPLIT offload was introduced some time >> ago to substitute bit-field header_split in struct rte_eth_rxmode. It allows to >> enable header split offload with the header size controlled using >> split_hdr_size in the same structure. >> >> Right now I see no single PMD which actually supports >> RTE_ETH_RX_OFFLOAD_HEADER_SPLIT with above definition. >> Many examples and test apps initialize the field to 0 explicitly. The most of >> drivers simply ignore split_hdr_size since the offload is not advertised, but >> some double-check that its value is 0. >> >> I think that it means that the field should be removed on the next LTS, and I'd >> say, together with the RTE_ETH_RX_OFFLOAD_HEADER_SPLIT offload bit. >> >> We should not redefine the offload meaning. > > Yes, you are right. No single PMD supports RTE_ETH_RX_OFFLOAD_HEADER_SPLIT now. > Previously, I used this flag is to distinguish buffer split and header split. > The former supports multi-segments split by length and offset. offset is misleading here, since split offset is derived from segment lengths. Offset specified in segments is a different thing. > The later supports two segments split by proto and offset. > At this level, header split is a subset of buffer split. IMHO, generic definition of the header split should not limit it by just two segments. > > Since we shouldn't redefine the meaning of this offload, > I will use the RTE_ETH_RX_OFFLOAD_BUFFER_SPLIT flag. > The existence of tunnel needs to define a proto field in buffer split, > because some PMDs do not support split based on length and offset. Not sure that I fully understand, but I'm looking forward to review v5. >>> >>> For example, let's suppose we configured the Rx queue with the >>> following segments: >>> seg0 - pool0, off0=2B >>> seg1 - pool1, off1=128B >> >> Corresponding feature is named Rx buffer split. >> Does it mean that protocol type based header split requires Rx buffer split >> feature to be supported? > > Protocol type based header split does not requires Rx buffer split. > In previous design, the header split and buffer split are exclusive. > Because we only configure one split offload for one RX queue. > >> >>> >>> With header split type configured with RTE_ETH_RX_HEADER_SPLIT_UDP, >>> the packet consists of MAC_IP_UDP_PAYLOAD will be split like following: >>> seg0 - udp header @ RTE_PKTMBUF_HEADROOM + 2 in mbuf from >> pool0 >>> seg1 - payload @ 128 in mbuf from pool1 >> >> Is it always outermost UDP? Does it require both UDP over IPv4 and UDP over >> IPv6 to be supported? What will happen if only one is supported? How >> application can find out which protocol stack are supported? > > Both inner and outer UDP are considered. > Current design does not distinguish UDP over IPv4 or IPv6. > If we want to support granularity like only IPv4 or IPv6 supported, > user need add more configurations. You should make it clear for application how to use it. What happens if unsupported packet is received on an RxQ configured to do header split? > > If application want to find out which protocol stack is supported, > one way I think is to expose the protocol stack supported by the driver through dev_info. > Any thoughts are welcomed :) dev_info is nice, but very heavily overloaded. We can start from dev_info and understand if it should be factored out to a separate API or it is OK to have it in dev_info if it just few simple fields. >> >>> >>> The memory attributes for the split parts may differ either - for >>> example the mempool0 and mempool1 belong to dpdk memory and >> external >>> memory, respectively. >>> >>> Signed-off-by: Xuan Ding >>> Signed-off-by: Yuan Wang >>> Signed-off-by: Wenxuan Wu >>> Reviewed-by: Qi Zhang >>> --- >>> lib/ethdev/rte_ethdev.c | 34 ++++++++++++++++++++++------- >>> lib/ethdev/rte_ethdev.h | 48 >> +++++++++++++++++++++++++++++++++++++++-- >>> 2 files changed, 72 insertions(+), 10 deletions(-) >>> >>> diff --git a/lib/ethdev/rte_ethdev.c b/lib/ethdev/rte_ethdev.c index >>> 29a3d80466..29adcdc2f0 100644 >>> --- a/lib/ethdev/rte_ethdev.c >>> +++ b/lib/ethdev/rte_ethdev.c >>> @@ -1661,6 +1661,7 @@ rte_eth_rx_queue_check_split(const struct >> rte_eth_rxseg_split *rx_seg, >>> struct rte_mempool *mpl = rx_seg[seg_idx].mp; >>> uint32_t length = rx_seg[seg_idx].length; >>> uint32_t offset = rx_seg[seg_idx].offset; >>> + uint16_t proto = rx_seg[seg_idx].proto; >>> >>> if (mpl == NULL) { >>> RTE_ETHDEV_LOG(ERR, "null mempool pointer\n"); >> @@ -1694,13 >>> +1695,29 @@ rte_eth_rx_queue_check_split(const struct >> rte_eth_rxseg_split *rx_seg, >>> } >>> offset += seg_idx != 0 ? 0 : RTE_PKTMBUF_HEADROOM; >>> *mbp_buf_size = rte_pktmbuf_data_room_size(mpl); >>> - length = length != 0 ? length : *mbp_buf_size; >>> - if (*mbp_buf_size < length + offset) { >>> - RTE_ETHDEV_LOG(ERR, >>> - "%s mbuf_data_room_size %u < %u >> (segment length=%u + segment offset=%u)\n", >>> - mpl->name, *mbp_buf_size, >>> - length + offset, length, offset); >>> - return -EINVAL; >>> + if (proto == RTE_ETH_RX_HEADER_SPLIT_NONE) { >>> + /* Check buffer split. */ >>> + length = length != 0 ? length : *mbp_buf_size; >>> + if (*mbp_buf_size < length + offset) { >>> + RTE_ETHDEV_LOG(ERR, >>> + "%s mbuf_data_room_size %u < %u >> (segment length=%u + segment offset=%u)\n", >>> + mpl->name, *mbp_buf_size, >>> + length + offset, length, offset); >>> + return -EINVAL; >>> + } >>> + } else { >>> + /* Check header split. */ >>> + if (length != 0) { >>> + RTE_ETHDEV_LOG(ERR, "segment length >> should be set to zero in header split\n"); >>> + return -EINVAL; >>> + } >>> + if (*mbp_buf_size < offset) { >>> + RTE_ETHDEV_LOG(ERR, >>> + "%s mbuf_data_room_size %u < %u >> segment offset)\n", >>> + mpl->name, *mbp_buf_size, >>> + offset); >>> + return -EINVAL; >>> + } >>> } >>> } >>> return 0; >>> @@ -1778,7 +1795,8 @@ rte_eth_rx_queue_setup(uint16_t port_id, >> uint16_t rx_queue_id, >>> rx_seg = (const struct rte_eth_rxseg_split *)rx_conf->rx_seg; >>> n_seg = rx_conf->rx_nseg; >>> >>> - if (rx_conf->offloads & RTE_ETH_RX_OFFLOAD_BUFFER_SPLIT) >> { >>> + if (rx_conf->offloads & RTE_ETH_RX_OFFLOAD_BUFFER_SPLIT >> || >>> + rx_conf->offloads & >> RTE_ETH_RX_OFFLOAD_HEADER_SPLIT) { >>> ret = rte_eth_rx_queue_check_split(rx_seg, n_seg, >>> &mbp_buf_size, >>> &dev_info); >>> diff --git a/lib/ethdev/rte_ethdev.h b/lib/ethdev/rte_ethdev.h index >>> 04cff8ee10..e8371b98ed 100644 >>> --- a/lib/ethdev/rte_ethdev.h >>> +++ b/lib/ethdev/rte_ethdev.h >>> @@ -1197,12 +1197,31 @@ struct rte_eth_txmode { >>> * - pool from the last valid element >>> * - the buffer size from this pool >>> * - zero offset >>> + * >>> + * Header split is a subset of buffer split. The split happens after >>> + the >>> + * packet header and before the packet payload. For PMDs that do not >>> + * support header split configuration by length, the location of the >>> + split >>> + * needs to be specified by the header protocol type. While for >>> + buffer split, >>> + * this field should not be configured. >>> + * >>> + * If RTE_ETH_RX_OFFLOAD_HEADER_SPLIT flag is set in offloads field, >>> + * the PMD will split the received packets into two separate regions: >>> + * - The header buffer will be allocated from the memory pool, >>> + * specified in the first array element, the second buffer, from the >>> + * pool in the second element. >>> + * >>> + * - The lengths do not need to be configured in header split. >>> + * >>> + * - The offsets from the segment description elements specify >>> + * the data offset from the buffer beginning except the first mbuf. >>> + * The first segment offset is added with RTE_PKTMBUF_HEADROOM. >>> */ >>> struct rte_eth_rxseg_split { >>> struct rte_mempool *mp; /**< Memory pool to allocate segment >> from. */ >>> uint16_t length; /**< Segment data length, configures split point. */ >>> uint16_t offset; /**< Data offset from beginning of mbuf data buffer. >> */ >>> - uint32_t reserved; /**< Reserved field. */ >>> + uint16_t proto; /**< header protocol type, configures header split >>> +point. */ >> >> I realize that you don't want to use here enum defined above to save some >> reserved space, but description must refer to the enum >> rte_eth_rx_header_split_protocol_type. > > Thanks for your suggestion, will fix it in next version. > >> >>> + uint16_t reserved; /**< Reserved field. */ >> >> As far as I can see the structure is experimental. So, it should not be the >> problem to extend it, but it is a really good question raised by Stephen in RFC >> v1 discussion. >> Shouldn't we require that all reserved fields are initialized to zero and >> ignored on processing? Frankly speaking I always thought so, but failed to >> find the place were it is documented. > > Yes, it can be documented. By default is should be zero, and we can configure > it to enable protocol type based buffer split. > >> >> @Thomas, @David, @Ferruh? >> >>> }; >>> >>> /** >>> @@ -1212,7 +1231,7 @@ struct rte_eth_rxseg_split { >>> * A common structure used to describe Rx packet segment properties. >>> */ >>> union rte_eth_rxseg { >>> - /* The settings for buffer split offload. */ >>> + /* The settings for buffer split and header split offload. */ >>> struct rte_eth_rxseg_split split; >>> /* The other features settings should be added here. */ >>> }; >>> @@ -1664,6 +1683,31 @@ struct rte_eth_conf { >>> RTE_ETH_RX_OFFLOAD_QINQ_STRIP) >>> #define DEV_RX_OFFLOAD_VLAN >> RTE_DEPRECATED(DEV_RX_OFFLOAD_VLAN) >>> RTE_ETH_RX_OFFLOAD_VLAN >>> >>> +/** >>> + * @warning >>> + * @b EXPERIMENTAL: this enum may change without prior notice. >>> + * This enum indicates the header split protocol type */ enum >>> +rte_eth_rx_header_split_protocol_type { >>> + RTE_ETH_RX_HEADER_SPLIT_NONE = 0, >>> + RTE_ETH_RX_HEADER_SPLIT_MAC, >>> + RTE_ETH_RX_HEADER_SPLIT_IPV4, >>> + RTE_ETH_RX_HEADER_SPLIT_IPV6, >>> + RTE_ETH_RX_HEADER_SPLIT_L3, >>> + RTE_ETH_RX_HEADER_SPLIT_TCP, >>> + RTE_ETH_RX_HEADER_SPLIT_UDP, >>> + RTE_ETH_RX_HEADER_SPLIT_SCTP, >>> + RTE_ETH_RX_HEADER_SPLIT_L4, >>> + RTE_ETH_RX_HEADER_SPLIT_INNER_MAC, >>> + RTE_ETH_RX_HEADER_SPLIT_INNER_IPV4, >>> + RTE_ETH_RX_HEADER_SPLIT_INNER_IPV6, >>> + RTE_ETH_RX_HEADER_SPLIT_INNER_L3, >>> + RTE_ETH_RX_HEADER_SPLIT_INNER_TCP, >>> + RTE_ETH_RX_HEADER_SPLIT_INNER_UDP, >>> + RTE_ETH_RX_HEADER_SPLIT_INNER_SCTP, >>> + RTE_ETH_RX_HEADER_SPLIT_INNER_L4, >> >> Enumeration members should be documented. See my question in the patch >> description. > > Thanks for your detailed comments, questions are answered accordingly. > > Best Regards, > Xuan > >> >>> +}; >>> + >>> /* >>> * If new Rx offload capabilities are defined, they also must be >>> * mentioned in rte_rx_offload_names in rte_ethdev.c file. >