From: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>
To: "Xing, Beilei" <beilei.xing@intel.com>,
Yong Wang <yongwang@vmware.com>,
Olivier Matz <olivier.matz@6wind.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: Mon, 20 Jun 2016 08:05:06 +0000 [thread overview]
Message-ID: <2601191342CEEE43887BDE71AB97725836B7346B@irsmsx105.ger.corp.intel.com> (raw)
In-Reply-To: <94479800C636CB44BD422CB454846E013A2DDF@SHSMSX101.ccr.corp.intel.com>
> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Xing, Beilei
> Sent: Monday, June 20, 2016 5:50 AM
> To: Yong Wang; Olivier Matz; Wu, Jingjing
> Cc: dev@dpdk.org; Julien Meunier; Thomas Monjalon
> Subject: Re: [dpdk-dev] [PATCH v3] i40e: configure MTU
>
>
> > -----Original Message-----
> > From: Yong Wang [mailto:yongwang@vmware.com]
> > Sent: Friday, June 17, 2016 1:40 AM
> > To: Olivier Matz <olivier.matz@6wind.com>; Xing, Beilei <beilei.xing@intel.com>;
> > Wu, Jingjing <jingjing.wu@intel.com>
> > Cc: dev@dpdk.org; Julien Meunier <julien.meunier@6wind.com>; Thomas
> > Monjalon <thomas.monjalon@6wind.com>
> > Subject: Re: [dpdk-dev] [PATCH v3] i40e: configure MTU
> >
> > 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 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.
> >
> Hi,
> For ixgbe/igb, there's register for MTU during runtime, but for i40e, setting MTU is finished by firmware during configuration. There'll
> be some risk when disable the port, reconfigure and re-enable the port, so return error code in this case currently.
Ok, but then what is the point to introduce mtu_set() for i40e at all?
Let's just leave it unimplemented, as it is right now.
Then users would know that for that device they have to do dev_stop/dev_configure().
Konstantin
> Thanks for your comments, we'll improve the document later.
>
> > >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:[~2016-06-20 8:05 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
2016-06-20 4:49 ` Xing, Beilei
2016-06-20 4:59 ` Xing, Beilei
2016-06-20 8:05 ` Ananyev, Konstantin [this message]
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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