From: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>
To: Yong Wang <yongwang@vmware.com>,
Olivier Matz <olivier.matz@6wind.com>,
"Xing, Beilei" <beilei.xing@intel.com>,
"Wu, Jingjing" <jingjing.wu@intel.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
Julien Meunier <julien.meunier@6wind.com>,
Thomas Monjalon <thomas.monjalon@6wind.com>
Subject: Re: [dpdk-dev] [PATCH v3] i40e: configure MTU
Date: Fri, 17 Jun 2016 00:03:30 +0000 [thread overview]
Message-ID: <2601191342CEEE43887BDE71AB97725836B72754@irsmsx105.ger.corp.intel.com> (raw)
In-Reply-To: <6A233AB2-6611-44DB-80F8-2AFDCF6EB8B0@vmware.com>
> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Yong Wang
> Sent: Thursday, June 16, 2016 6:52 PM
> To: Olivier Matz; Xing, Beilei; Wu, Jingjing
> Cc: dev@dpdk.org; Julien Meunier; Thomas Monjalon
> Subject: Re: [dpdk-dev] [PATCH v3] i40e: configure MTU
>
> On 6/16/16, 10:40 AM, "dev on behalf of Yong Wang" <dev-bounces@dpdk.org on behalf of yongwang@vmware.com> wrote:
>
> >On 5/16/16, 5:27 AM, "dev on behalf of Olivier Matz" <dev-bounces@dpdk.org on behalf of olivier.matz@6wind.com> wrote:
> >
> >>Hi Beilei,
> >>
> >>On 05/13/2016 10:15 AM, Beilei Xing wrote:
> >>> This patch enables configuring MTU for i40e.
> >>> Since changing MTU needs to reconfigure queue, stop port first
> >>> before configuring MTU.
> >>>
> >>> Signed-off-by: Beilei Xing <beilei.xing@intel.com>
> >>> ---
> >>> v3 changes:
> >>> Add frame size with extra I40E_VLAN_TAG_SIZE.
> >>> Delete i40e_dev_rx_init(pf) cause it will be called when port starts.
> >>>
> >>> v2 changes:
> >>> If mtu is not within the allowed range, return -EINVAL instead of -EBUSY.
> >>> Delete rxq reconfigure cause rxq reconfigure will be finished in
> >>> i40e_dev_rx_init.
> >>>
> >>> drivers/net/i40e/i40e_ethdev.c | 34 ++++++++++++++++++++++++++++++++++
> >>> 1 file changed, 34 insertions(+)
> >>>
> >>> [...]
> >>> +static int
> >>> +i40e_dev_mtu_set(struct rte_eth_dev *dev, uint16_t mtu)
> >>> +{
> >>> + struct i40e_pf *pf = I40E_DEV_PRIVATE_TO_PF(dev->data->dev_private);
> >>> + struct rte_eth_dev_data *dev_data = pf->dev_data;
> >>> + uint32_t frame_size = mtu + ETHER_HDR_LEN
> >>> + + ETHER_CRC_LEN + I40E_VLAN_TAG_SIZE;
> >>> + int ret = 0;
> >>> +
> >>> + /* check if mtu is within the allowed range */
> >>> + if ((mtu < ETHER_MIN_MTU) || (frame_size > I40E_FRAME_SIZE_MAX))
> >>> + return -EINVAL;
> >>> +
> >>> + /* mtu setting is forbidden if port is start */
> >>> + if (dev_data->dev_started) {
> >>> + PMD_DRV_LOG(ERR,
> >>> + "port %d must be stopped before configuration\n",
> >>> + dev_data->port_id);
> >>> + return -ENOTSUP;
> >>> + }
> >>
> >>I'm not convinced that ENOTSUP is the proper return value here.
> >>It is usually returned when a function is not implemented, which
> >>is not the case here: the function is implemented but is forbidden
> >>because the port is running.
> >>
> >>I saw that Julien commented on your v1 that the return value should
> >>be one of:
> >> - (0) if successful.
> >> - (-ENOTSUP) if operation is not supported.
> >> - (-ENODEV) if *port_id* invalid.
> >> - (-EINVAL) if *mtu* invalid.
> >>
> >>But I think your initial value (-EBUSY) was fine. Maybe it should be
> >>added in the API instead, with the following description:
> >> (-EBUSY) if the operation is not allowed when the port is running
> >
> >AFAICT, the same check is not done for other drivers that implement
> >the mac_set op. Wouldn’t it make more sense to have the driver disable
>
> Correction: this should read as mtu_set.
>
> >the port, reconfigure and re-enable it in this case, instead of returning
> >error code? If the consensus in DPDK is to have the application disable
> >the port first, we need to enforce this policy across all devices and
> >clearly document this behavior.
Other PMDs do allow to change mtu without stopping/reconfiguration the port
(under certain conditions of course).
As I remember that's why that function was introduced at the first place.
It is a bit strange that i40e doesn't allow that, might be the author can
comment why it is necessary.
Again the whole i40e_dev_mtu_set() looks a bit strange to me -
I can't see where the actual change of HW state is happening.
Konstantin
> >
> >>This would allow the application to take its dispositions to stop the
> >>port and restart it with the proper jumbo_frame argument.
> >>
> >>+CC Thomas which maintains ethdev API.
> >>
> >>
> >>Regards,
> >>Olivier
> >
next prev parent reply other threads:[~2016-06-17 0:03 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-23 11:26 [dpdk-dev] [PATCH] " Beilei Xing
2016-04-26 2:00 ` Wu, Jingjing
2016-04-27 11:43 ` Julien Meunier
2016-04-27 15:01 ` Xing, Beilei
2016-04-28 3:19 ` [dpdk-dev] [PATCH V2] " Beilei Xing
2016-05-13 8:15 ` [dpdk-dev] [PATCH v3] " Beilei Xing
2016-05-16 12:27 ` Olivier Matz
2016-06-16 17:40 ` Yong Wang
2016-06-16 17:51 ` Yong Wang
2016-06-17 0:03 ` Ananyev, Konstantin [this message]
2016-06-20 4:49 ` Xing, Beilei
2016-06-20 4:59 ` Xing, Beilei
2016-06-20 8:05 ` Ananyev, Konstantin
2016-06-20 12:04 ` Xing, Beilei
2016-06-20 12:15 ` Ananyev, Konstantin
2016-06-20 12:46 ` Xing, Beilei
2016-05-20 15:17 ` [dpdk-dev] [PATCH v4] " Beilei Xing
2016-05-23 1:33 ` Wu, Jingjing
2016-06-09 14:23 ` Bruce Richardson
2016-06-23 10:13 ` Bruce Richardson
2016-06-23 13:37 ` Xing, Beilei
2016-06-23 13:44 ` Bruce Richardson
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