Hi Konstantin, > -----Original Message----- > From: Ananyev, Konstantin > Sent: Monday, June 20, 2016 8:15 PM > To: Xing, Beilei <beilei.xing at intel.com>; Yong Wang <yongwang at > vmware.com>; > Olivier Matz <olivier.matz at 6wind.com>; Wu, Jingjing <jingjing.wu at > intel.com> > Cc: dev at dpdk.org; Julien Meunier <julien.meunier at 6wind.com>; Thomas > Monjalon <thomas.monjalon at 6wind.com> > Subject: RE: [dpdk-dev] [PATCH v3] i40e: configure MTU > > Hi Beilei, > > > -----Original Message----- > > From: Xing, Beilei > > Sent: Monday, June 20, 2016 1:05 PM > > To: Ananyev, Konstantin; Yong Wang; Olivier Matz; Wu, Jingjing > > Cc: dev at dpdk.org; Julien Meunier; Thomas Monjalon > > Subject: RE: [dpdk-dev] [PATCH v3] i40e: configure MTU > > > > > > > -----Original Message----- > > > From: Ananyev, Konstantin > > > Sent: Monday, June 20, 2016 4:05 PM > > > To: Xing, Beilei <beilei.xing at intel.com>; Yong Wang > > > <yongwang at vmware.com>; Olivier Matz <olivier.matz at 6wind.com>; Wu, > > > Jingjing <jingjing.wu at intel.com> > > > Cc: dev at dpdk.org; Julien Meunier <julien.meunier at 6wind.com>; Thomas > > > Monjalon <thomas.monjalon at 6wind.com> > > > Subject: RE: [dpdk-dev] [PATCH v3] i40e: configure MTU > > > > > > > > > > > > > -----Original Message----- > > > > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Xing, Beilei > > > > Sent: Monday, June 20, 2016 5:50 AM > > > > To: Yong Wang; Olivier Matz; Wu, Jingjing > > > > Cc: dev at dpdk.org; Julien Meunier; Thomas Monjalon > > > > Subject: Re: [dpdk-dev] [PATCH v3] i40e: configure MTU > > > > > > > > > > > > > -----Original Message----- > > > > > From: Yong Wang [mailto:yongwang at vmware.com] > > > > > Sent: Friday, June 17, 2016 1:40 AM > > > > > To: Olivier Matz <olivier.matz at 6wind.com>; Xing, Beilei > > > > > <beilei.xing at intel.com>; Wu, Jingjing <jingjing.wu at intel.com> > > > > > Cc: dev at dpdk.org; Julien Meunier <julien.meunier at 6wind.com>; > > > > > Thomas Monjalon <thomas.monjalon at 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 at dpdk.org on behalf of olivier.matz at 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 at 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(). > > > > Hi Konstantin, > > The original intention is to reduce ops gap in different PMDs, but > > unfortunately, setting MTU in i40e couldn?t be finished as in ixgbe, > > Yes, I understand that from your previous explanation. > > > so in the function, we change the configuration and note users that if want > > to > configure MTU, stop ports first. > > Well, you can do that now with dev_stop(); dev_configure(), right?
Yes, that's right. > As I remember, the original intention of mtu_set() was to give user an > ability to > change mtu (whenever possible) without stopping the port. > If the HW (i40e) doesn't support it - that's fine, we just leave mtu_set() > for i40e > unimplemented. > > > The sequence of > configuring MTU for i40e is: port stop->set MTU->port > > start. > > We will add according instruction in document. > > Sorry, but I don?t agree here. > I think, in that case it is better just to leave mtu_set() unimplemented for > i40e. OK, I'll discuss with maintainer for this case. Thanks for all your points:) Beilei > Konstantin > > > Beilei > > > > > 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
