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01 May 2020 09:04:22 -0700 From: Ferruh Yigit To: oulijun , Andrew Rybchenko , thomas@monjalon.net Cc: dev@dpdk.org, linuxarm@huawei.com References: <1587990889-56408-1-git-send-email-oulijun@huawei.com> <909bd3c1-6ed4-15a4-d706-39d68e8deff5@intel.com> <59c19bbe-281a-9258-385c-47ce9b9c5889@huawei.com> <7be2b2bb-80d4-aa45-b018-0e3dffc7a8fb@intel.com> Autocrypt: addr=ferruh.yigit@intel.com; prefer-encrypt=mutual; keydata= mQINBFXZCFABEADCujshBOAaqPZpwShdkzkyGpJ15lmxiSr3jVMqOtQS/sB3FYLT0/d3+bvy qbL9YnlbPyRvZfnP3pXiKwkRoR1RJwEo2BOf6hxdzTmLRtGtwWzI9MwrUPj6n/ldiD58VAGQ +iR1I/z9UBUN/ZMksElA2D7Jgg7vZ78iKwNnd+vLBD6I61kVrZ45Vjo3r+pPOByUBXOUlxp9 GWEKKIrJ4eogqkVNSixN16VYK7xR+5OUkBYUO+sE6etSxCr7BahMPKxH+XPlZZjKrxciaWQb +dElz3Ab4Opl+ZT/bK2huX+W+NJBEBVzjTkhjSTjcyRdxvS1gwWRuXqAml/sh+KQjPV1PPHF YK5LcqLkle+OKTCa82OvUb7cr+ALxATIZXQkgmn+zFT8UzSS3aiBBohg3BtbTIWy51jNlYdy ezUZ4UxKSsFuUTPt+JjHQBvF7WKbmNGS3fCid5Iag4tWOfZoqiCNzxApkVugltxoc6rG2TyX CmI2rP0mQ0GOsGXA3+3c1MCdQFzdIn/5tLBZyKy4F54UFo35eOX8/g7OaE+xrgY/4bZjpxC1 1pd66AAtKb3aNXpHvIfkVV6NYloo52H+FUE5ZDPNCGD0/btFGPWmWRmkPybzColTy7fmPaGz cBcEEqHK4T0aY4UJmE7Ylvg255Kz7s6wGZe6IR3N0cKNv++O7QARAQABtCVGZXJydWggWWln aXQgPGZlcnJ1aC55aWdpdEBpbnRlbC5jb20+iQJsBBMBCgBWAhsDAh4BAheABQsJCAcDBRUK CQgLBRYCAwEABQkKqZZ8FiEE0jZTh0IuwoTjmYHH+TPrQ98TYR8FAl6ha3sXGHZrczovL2tl eXMub3BlbnBncC5vcmcACgkQ+TPrQ98TYR8uLA//QwltuFliUWe60xwmu9sY38c1DXvX67wk UryQ1WijVdIoj4H8cf/s2KtyIBjc89R254KMEfJDao/LrXqJ69KyGKXFhFPlF3VmFLsN4XiT PSfxkx8s6kHVaB3O183p4xAqnnl/ql8nJ5ph9HuwdL8CyO5/7dC/MjZ/mc4NGq5O9zk3YRGO lvdZAp5HW9VKW4iynvy7rl3tKyEqaAE62MbGyfJDH3C/nV/4+mPc8Av5rRH2hV+DBQourwuC ci6noiDP6GCNQqTh1FHYvXaN4GPMHD9DX6LtT8Fc5mL/V9i9kEVikPohlI0WJqhE+vQHFzR2 1q5nznE+pweYsBi3LXIMYpmha9oJh03dJOdKAEhkfBr6n8BWkWQMMiwfdzg20JX0o7a/iF8H 4dshBs+dXdIKzPfJhMjHxLDFNPNH8zRQkB02JceY9ESEah3wAbzTwz+e/9qQ5OyDTQjKkVOo cxC2U7CqeNt0JZi0tmuzIWrfxjAUulVhBmnceqyMOzGpSCQIkvalb6+eXsC9V1DZ4zsHZ2Mx Hi+7pCksdraXUhKdg5bOVCt8XFmx1MX4AoV3GWy6mZ4eMMvJN2hjXcrreQgG25BdCdcxKgqp e9cMbCtF+RZax8U6LkAWueJJ1QXrav1Jk5SnG8/5xANQoBQKGz+yFiWcgEs9Tpxth15o2v59 gXK5Ag0EV9ZMvgEQAKc0Db17xNqtSwEvmfp4tkddwW9XA0tWWKtY4KUdd/jijYqc3fDD54ES YpV8QWj0xK4YM0dLxnDU2IYxjEshSB1TqAatVWz9WtBYvzalsyTqMKP3w34FciuL7orXP4Ai bPtrHuIXWQOBECcVZTTOdZYGAzaYzxiAONzF9eTiwIqe9/oaOjTwTLnOarHt16QApTYQSnxD UQljeNvKYt1lZE/gAUUxNLWsYyTT+22/vU0GDUahsJxs1+f1yEr+OGrFiEAmqrzpF0lCS3f/ 3HVTU6rS9cK3glVUeaTF4+1SK5ZNO35piVQCwphmxa+dwTG/DvvHYCtgOZorTJ+OHfvCnSVj sM4kcXGjJPy3JZmUtyL9UxEbYlrffGPQI3gLXIGD5AN5XdAXFCjjaID/KR1c9RHd7Oaw0Pdc q9UtMLgM1vdX8RlDuMGPrj5sQrRVbgYHfVU/TQCk1C9KhzOwg4Ap2T3tE1umY/DqrXQgsgH7 1PXFucVjOyHMYXXugLT8YQ0gcBPHy9mZqw5mgOI5lCl6d4uCcUT0l/OEtPG/rA1lxz8ctdFB VOQOxCvwRG2QCgcJ/UTn5vlivul+cThi6ERPvjqjblLncQtRg8izj2qgmwQkvfj+h7Ex88bI 8iWtu5+I3K3LmNz/UxHBSWEmUnkg4fJlRr7oItHsZ0ia6wWQ8lQnABEBAAGJAjwEGAEKACYC GwwWIQTSNlOHQi7ChOOZgcf5M+tD3xNhHwUCXqFrngUJCKxSYAAKCRD5M+tD3xNhH3YWD/9b cUiWaHJasX+OpiuZ1Li5GG3m9aw4lR/k2lET0UPRer2Jy1JsL+uqzdkxGvPqzFTBXgx/6Byz EMa2mt6R9BCyR286s3lxVS5Bgr5JGB3EkpPcoJT3A7QOYMV95jBiiJTy78Qdzi5LrIu4tW6H o0MWUjpjdbR01cnj6EagKrDx9kAsqQTfvz4ff5JIFyKSKEHQMaz1YGHyCWhsTwqONhs0G7V2 0taQS1bGiaWND0dIBJ/u0pU998XZhmMzn765H+/MqXsyDXwoHv1rcaX/kcZIcN3sLUVcbdxA WHXOktGTQemQfEpCNuf2jeeJlp8sHmAQmV3dLS1R49h0q7hH4qOPEIvXjQebJGs5W7s2vxbA 5u5nLujmMkkfg1XHsds0u7Zdp2n200VC4GQf8vsUp6CSMgjedHeF9zKv1W4lYXpHp576ZV7T GgsEsvveAE1xvHnpV9d7ZehPuZfYlP4qgo2iutA1c0AXZLn5LPcDBgZ+KQZTzm05RU1gkx7n gL9CdTzVrYFy7Y5R+TrE9HFUnsaXaGsJwOB/emByGPQEKrupz8CZFi9pkqPuAPwjN6Wonokv ChAewHXPUadcJmCTj78Oeg9uXR6yjpxyFjx3vdijQIYgi5TEGpeTQBymLANOYxYWYOjXk+ae dYuOYKR9nbPv+2zK9pwwQ2NXbUBystaGyQ== Message-ID: Date: Fri, 1 May 2020 17:04:21 +0100 MIME-Version: 1.0 In-Reply-To: <7be2b2bb-80d4-aa45-b018-0e3dffc7a8fb@intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Subject: Re: [dpdk-dev] [PATCH] ethdev: check for Rx RSS distribution and RSS hash X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 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 4/29/2020 1:42 PM, Ferruh Yigit wrote: > On 4/29/2020 7:41 AM, oulijun wrote: >> >> >> 在 2020/4/27 21:27, Ferruh Yigit 写道: >>> On 4/27/2020 1:49 PM, Andrew Rybchenko wrote: >>>> On 4/27/20 3:34 PM, Lijun Ou wrote: >>>>> When rte api checks the Rx RSS distribution is enable but the RSS >>>>> hash is disabled, it will return an error. >>>>> >>>>> Signed-off-by: Lijun Ou >>>>> --- >>>>> lib/librte_ethdev/rte_ethdev.c | 11 +++++++++++ >>>>> 1 file changed, 11 insertions(+) >>>>> >>>>> diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c >>>>> index 0854ef8..07734c4 100644 >>>>> --- a/lib/librte_ethdev/rte_ethdev.c >>>>> +++ b/lib/librte_ethdev/rte_ethdev.c >>>>> @@ -1411,6 +1411,17 @@ rte_eth_dev_configure(uint16_t port_id, uint16_t nb_rx_q, uint16_t nb_tx_q, >>>>> goto rollback; >>>>> } >>>>> >>>>> + /* Check if Rx RSS distribution is enable but RSS hash is disabled. */ >>>>> + if (((dev_conf->rxmode.mq_mode & ETH_MQ_RX_RSS_FLAG) != 0) && >>>>> + !(dev_conf->rxmode.offloads & DEV_RX_OFFLOAD_RSS_HASH)) { >>>>> + RTE_ETHDEV_LOG(ERR, >>>>> + "Ethdev port_id=%u config valid Rx mq_mode with RSS but %s offload is no-requested\n", >>>>> + port_id, >>>>> + rte_eth_dev_rx_offload_name(DEV_RX_OFFLOAD_RSS_HASH)); >>>>> + ret = -EINVAL; >>>>> + goto rollback; >>>>> + } >>>>> + >>>>> /* >>>>> * Setup new number of RX/TX queues and reconfigure device. >>>>> */ >>>> >>>> NACK. It is perfectly fine to do distribution, but do not need RSS hash >>>> information. >>>> - ETH_MQ_RX_RSS_FLAG controls RSS hash calculation and distribution >>>> - DEV_RX_OFFLOAD_RSS_HASH controls delivery of the hash value >>>> itself from HW to SW >>>> >>> >>> Hi Lijun, >>> >>> As Andrew described, now 'DEV_RX_OFFLOAD_RSS_HASH' controls to copy calculated >>> hash value to 'mbuf::hash::rss' or not. When rss hash copied to mubf, >>> 'PKT_RX_RSS_HASH' flag of 'mbuf::ol_flags' set to notify the application that >>> hash value is valid. This was a performance optimization. >>> >> if the user is not configure the DEV_RX_OFFLOAD_RSS_HASH and the users >> add the ETH_MQ_RX_RSS_FLAG， as a result, the hardware has calculated the >> hash result and distributed, the mbuf::o1_flags have set the >> PKT_RX_RSS_HASH and the mbuf::hash::rss have set the hash result. What >> are the advantage of this configuration with DEV_RX_OFFLOAD_RSS_HASH? > > If 'DEV_RX_OFFLOAD_RSS_HASH' NOT set, but 'ETH_MQ_RX_RSS_FLAG' set, RSS should > work as expected but 'mbuf::hash::rss' not filled. > > This is optimization for the case user doesn't need the calculated hash value, > and seems this optimization has bigger affect in some NICs that pays some cost > to receive the HW calculated hash values. > > User requesting 'DEV_RX_OFFLOAD_RSS_HASH' offload should enable driver to update > 'mbuf::hash::rss' and 'PKT_RX_RSS_HASH' in 'mbuf::ol_flags' addition to RSS feature. I hope this is clear now, and back to my first point if you think above behavior is not clear in the doc or API comments, can you please send a patch to clarify it better? Thanks, ferruh > >> >> Can I understand it this way, If the user does not apply this rss hash, >> does it mean that rss cannot be used to improve performance, even if the >> hardware has calculated the rss hash result? > > If 'DEV_RX_OFFLOAD_RSS_HASH' is NOT set, application won't able to receive the > HW calculated hash values. > >>> We know above because we were involved in development of it, if this is not >>> clean for third party, can you please amend your patch to clarify above behavior? >>> >>> Thanks, >>> ferruh >>> >>> . >>> >> >