From: Ferruh Yigit <ferruh.yigit@intel.com>
To: "Yang, SteveX" <stevex.yang@intel.com>,
Huisong Li <lihuisong@huawei.com>, "dev@dpdk.org" <dev@dpdk.org>
Cc: "Lu, Wenzhuo" <wenzhuo.lu@intel.com>,
"Li, Xiaoyun" <xiaoyun.li@intel.com>,
"Iremonger, Bernard" <bernard.iremonger@intel.com>,
"thomas@monjalon.net" <thomas@monjalon.net>,
"andrew.rybchenko@oktetlabs.ru" <andrew.rybchenko@oktetlabs.ru>,
"Yang, Qiming" <qiming.yang@intel.com>,
"oulijun@huawei.com" <oulijun@huawei.com>,
"huangdaode@huawei.com" <huangdaode@huawei.com>,
Lijun Ou <oulijun@huawei.com>
Subject: Re: [dpdk-dev] [PATCH v3 1/3] ethdev: fix MTU doesn't update when jumbo frame disabled
Date: Mon, 25 Jan 2021 12:38:08 +0000 [thread overview]
Message-ID: <ee99d245-73e7-6097-eb79-3926eaa5536d@intel.com> (raw)
In-Reply-To: <DM6PR11MB43628A600BAAEC75FFF1343BF9BD9@DM6PR11MB4362.namprd11.prod.outlook.com>
On 1/25/2021 9:49 AM, Yang, SteveX wrote:
> Hi Huisong,
>
> Thanks for your review.
>
> The validity of the pair <DEV_RX_OFFLOAD_JUMBO_FRAME, max_rx_pkt_len> should be
> checked from application layer (e.g.: testpmd),
>
> and the RTE layer should keep open enough to adapt the high-layer requirement.
>
> I’m not sure if exists some applications/NICs that treat ‘packet size < 1500’ as
> JUMBO_FRAME. If so, that also can work as expect with current code.
>
> @Yigit, Ferruh <mailto:ferruh.yigit@intel.com>, please correct me if something
> understand wrong.
>
Hi Huisong,
Agree that there is a grey area in the API, the question is if 'JUMBO_FRAME' is
set, can application set the 'max_rx_pkt_len' less than "RTE_ETHER_MTU +
overhead_len". Lijun (cc'ed) has the same concern.
The API documentation, and checks in the 'rte_eth_dev_configure()' enables
setting this for a long time, I am reluctant to add this limitation now.
Although agree that application should set 'JUMBO_FRAME' properly based on
requested 'MTU' value.
> BTW, there perhaps are some confused problems about jumbo frame and
> max_rx_pkt_len, and Ferruh has scheduled to re-factor this part at release 21.11.
>
> If you’re interesting about it, please refer to following link: [RFC,v2] doc:
> announce max Rx packet len field deprecation - Patchwork (dpdk.org)
> <http://patches.dpdk.org/patch/84522/>
>
> Thanks & Regards,
>
> Steve Yang.
>
> *From:* Huisong Li <lihuisong@huawei.com>
> *Sent:* Monday, January 25, 2021 3:12 PM
> *To:* Yang, SteveX <stevex.yang@intel.com>; dev@dpdk.org
> *Cc:* Lu, Wenzhuo <wenzhuo.lu@intel.com>; Li, Xiaoyun <xiaoyun.li@intel.com>;
> Iremonger, Bernard <bernard.iremonger@intel.com>; thomas@monjalon.net; Yigit,
> Ferruh <ferruh.yigit@intel.com>; andrew.rybchenko@oktetlabs.ru; Yang, Qiming
> <qiming.yang@intel.com>; oulijun@huawei.com; huangdaode@huawei.com
> *Subject:* Re: [dpdk-dev] [PATCH v3 1/3] ethdev: fix MTU doesn't update when
> jumbo frame disabled
>
> Hi Steve,
>
> In the current modification, the MTU is updated based on 'max_rx_pkt_len'
> regardless of whether jumbo frame is enabled.
>
> Now, MTU is correct when jumbo frmae is disabled. However, when jumbo frame is
> enabled, the MTU value may be inconsistent with
>
> the definition of the enabled jumbo frame. Like:
>
> 1/ DEV_RX_OFFLOAD_JUMBO_FRAME is set;
>
> 2/ max_rx_pkt_len = 1200
>
> 3/ dev->data->mtu = 1200 - overhead_len(18) = 1182
>
> In rte_eth_dev_configure API, the check for 'max_rx_pkt_len' is as follows:
>
> if (dev_conf->rxmode.offloads & DEV_RX_OFFLOAD_JUMBO_FRAME) { //jumbo frame enabled
> if (dev_conf->rxmode.max_rx_pkt_len > dev_info.max_rx_pktlen) {
> xxxx
> goto rollback;
> } else if (*dev_conf->rxmode.max_rx_pkt_len < RTE_ETHER_MIN_LEN*) {
> xxxx
> goto rollback;
> }
> } else { //jumbo frame disabled
>
> if (pktlen < RTE_ETHER_MIN_MTU + overhead_len ||
> pktlen > RTE_ETHER_MTU + overhead_len)
> /* Use default value */
> dev->data->dev_conf.rxmode.max_rx_pkt_len =
> RTE_ETHER_MTU + overhead_len;
>
> }
>
> Since the applicatin sets DEV_RX_OFFLOAD_JUMBO_FRAME to enable jumbo frame, and
> the framework API needs to update
>
> the MTU based on 'max_rx_pkt_len', but the framework API uses
> *RTE_ETHER_MIN_LEN(64)* to verify the boundary value of
>
> 'max_rx_pkt_len', instead of "RTE_ETHER_MTU + overhead_len". As far as I know,
> if the applicatin sets DEV_RX_OFFLOAD_JUMBO_FRAME
>
> and 'max_rx_pkt_len' is 1200, the framework API or driver should return a
> failure. As mentioned in this patch set, the jumbo frame
>
> offload is set only when 'max_rx_pkt_len' requested is greater than
> "RTE_ETHER_MTU + eth_overhead" in testpmd.
>
> I really don't understand it. How do you understand this behavior?
>
> Thanks.
>
> 在 2021/1/22 17:01, Steve Yang 写道:
>
> The MTU value should be updated to 'max_rx_pkt_len - overhead'
>
> no matter if the JUMBO FRAME offload enabled. If not update this MTU,
>
> use will get the wrong MTU info via some command.
>
> E.g.: 'show port info all' in testpmd tool.
>
> Actually, the 'max_rx_pkt_len' has been used for other purposes in many
>
> places now, even though the 'max_rx_pkt_len' is expected 'Only used if
>
> JUMBO_FRAME enabled'.
>
> For examples,
>
> 'max_rx_pkt_len' perhaps can be used as the 'rx_ctx.rxmax' in i40e.
>
> Fixes: bf0f90d92d30 ("ethdev: fix max Rx packet length check")
>
> Signed-off-by: Steve Yang<stevex.yang@intel.com> <mailto:stevex.yang@intel.com>
>
> ---
>
> lib/librte_ethdev/rte_ethdev.c | 8 ++++----
>
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
>
> index daf5f24f7e..42857e3b67 100644
>
> --- a/lib/librte_ethdev/rte_ethdev.c
>
> +++ b/lib/librte_ethdev/rte_ethdev.c
>
> @@ -1421,10 +1421,6 @@ rte_eth_dev_configure(uint16_t port_id, uint16_t nb_rx_q, uint16_t nb_tx_q,
>
> ret = -EINVAL;
>
> goto rollback;
>
> }
>
> -
>
> - /* Scale the MTU size to adapt max_rx_pkt_len */
>
> - dev->data->mtu = dev->data->dev_conf.rxmode.max_rx_pkt_len -
>
> - overhead_len;
>
> } else {
>
> uint16_t pktlen = dev_conf->rxmode.max_rx_pkt_len;
>
> if (pktlen < RTE_ETHER_MIN_MTU + overhead_len ||
>
> @@ -1434,6 +1430,10 @@ rte_eth_dev_configure(uint16_t port_id, uint16_t nb_rx_q, uint16_t nb_tx_q,
>
> RTE_ETHER_MTU + overhead_len;
>
> }
>
>
>
> + /* Scale the MTU size to adapt max_rx_pkt_len */
>
> + dev->data->mtu = dev->data->dev_conf.rxmode.max_rx_pkt_len -
>
> + overhead_len;
>
> +
>
> /*
>
> * If LRO is enabled, check that the maximum aggregated packet
>
> * size is supported by the configured device.
>
next prev parent reply other threads:[~2021-01-25 12:38 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-22 8:13 [dpdk-dev] [PATCH v1] app/testpmd: fix dynamic config error for max-pkt-len Steve Yang
2020-12-23 2:27 ` Li, Xiaoyun
2020-12-23 8:51 ` [dpdk-dev] [PATCH v2] app/testpmd: fix dynamic config error Steve Yang
2020-12-23 9:00 ` Li, Xiaoyun
2021-01-13 8:13 ` Chen, BoX C
2021-01-19 15:44 ` Ferruh Yigit
2021-01-22 9:01 ` [dpdk-dev] [PATCH v3 0/3] fix 'max-pkt-len' errors Steve Yang
2021-01-22 9:01 ` [dpdk-dev] [PATCH v3 1/3] ethdev: fix MTU doesn't update when jumbo frame disabled Steve Yang
2021-01-25 7:12 ` Huisong Li
[not found] ` <DM6PR11MB43628A600BAAEC75FFF1343BF9BD9@DM6PR11MB4362.namprd11.prod.outlook.com>
2021-01-25 12:38 ` Ferruh Yigit [this message]
2021-01-22 9:01 ` [dpdk-dev] [PATCH v3 2/3] app/testpmd: fix max-pkt-len option invalid Steve Yang
2021-01-22 9:01 ` [dpdk-dev] [PATCH v3 3/3] app/testpmd: fix dynamic config error Steve Yang
2021-01-22 17:04 ` Ferruh Yigit
2021-01-22 17:15 ` Ferruh Yigit
2021-01-25 8:32 ` [dpdk-dev] [PATCH v4 0/2] fix 'max-pkt-len' errors Steve Yang
2021-01-25 8:32 ` [dpdk-dev] [PATCH v4 1/2] ethdev: fix MTU doesn't update when jumbo frame disabled Steve Yang
2021-01-25 12:41 ` Ferruh Yigit
2021-01-25 8:32 ` [dpdk-dev] [PATCH v4 2/2] app/testpmd: fix max-pkt-len option invalid Steve Yang
2021-01-25 14:45 ` Ferruh Yigit
2021-01-25 15:46 ` Lance Richardson
2021-01-25 17:57 ` Ferruh Yigit
2021-01-25 18:15 ` [dpdk-dev] [PATCH v5] app/testpmd: fix setting maximum packet length Ferruh Yigit
2021-01-25 19:41 ` Lance Richardson
2021-01-26 0:44 ` Ferruh Yigit
2021-01-26 3:22 ` Lance Richardson
2021-01-26 3:45 ` Lance Richardson
2021-01-26 7:54 ` Li, Xiaoyun
2021-01-26 11:01 ` Ferruh Yigit
2021-01-28 21:36 ` Lance Richardson
2021-01-28 22:12 ` [dpdk-dev] [dpdk-stable] " Ferruh Yigit
2021-01-26 9:02 ` [dpdk-dev] " Wisam Monther
2021-01-27 3:04 ` Li, Xiaoyun
2021-01-28 1:57 ` Chen, BoX C
2021-01-28 9:18 ` Wisam Monther
2021-01-28 9:26 ` Ferruh Yigit
2021-01-28 11:08 ` Wisam Monther
2021-01-28 12:07 ` [dpdk-dev] [PATCH v6] " Ferruh Yigit
2021-01-29 9:34 ` Ferruh Yigit
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