From: "Dey, Souvik" <sodey@sonusnet.com>
To: Yuanhan Liu <yuanhan.liu@linux.intel.com>,
Stephen Hemminger <stephen@networkplumber.org>
Cc: "Kavanagh, Mark B" <mark.b.kavanagh@intel.com>,
"dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH v6] net/virtio: add set_mtu in virtio
Date: Tue, 27 Sep 2016 15:41:07 +0000 [thread overview]
Message-ID: <BN3PR03MB1494659D87DE9555FCC071D0DACC0@BN3PR03MB1494.namprd03.prod.outlook.com> (raw)
In-Reply-To: <20160926032128.GH23158@yliu-dev.sh.intel.com>
Hi All,
Any further updates/comments on this ?
--
Regards,
Souvik
-----Original Message-----
From: Yuanhan Liu [mailto:yuanhan.liu@linux.intel.com]
Sent: Sunday, September 25, 2016 11:21 PM
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: Dey, Souvik <sodey@sonusnet.com>; Kavanagh, Mark B <mark.b.kavanagh@intel.com>; dev@dpdk.org
Subject: Re: [PATCH v6] net/virtio: add set_mtu in virtio
Hi Stephen,
Are you okay with this change?
--yliu
On Fri, Sep 23, 2016 at 03:17:37PM +0000, Dey, Souvik wrote:
> Hi Liu/Mark/Stephen,
>
> I have tried to modify the code with all of your latest comments.
> Do let me know if this looks fine or you have more comments.
>
>
>
> Changes done :
>
> -- max frame ize is compare to VIRTIO_MAX_RX_PKTLEN instead of
> dev_info.max_rx_pktlen
>
> -- removed the CRC_LEN from the ether_len calculation and added the
> merge rx buf hdr len. ether_hdr_len = ETHER_HDR_LEN + VLAN_TAG_SIZE +
> hw->vtnet_hdr_size
>
> -- Still retained the VLAN Size as the worst case scenario.
>
>
>
>
>
> --
>
> drivers/net/virtio/virtio_ethdev.c | 16 ++++++++++++++++
>
> 1 file changed, 16 insertions(+)
>
>
>
> diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/
> virtio_ethdev.c
>
> index 423c597..1dbfea6 100644
>
> --- a/drivers/net/virtio/virtio_ethdev.c
>
> +++ b/drivers/net/virtio/virtio_ethdev.c
>
> @@ -653,12 +653,20 @@ virtio_dev_allmulticast_disable(struct
> rte_eth_dev *dev)
>
> PMD_INIT_LOG(ERR, "Failed to disable allmulticast");
>
> }
>
>
>
> +#define VLAN_TAG_SIZE 4 /* 802.3ac tag (not DMA'd) */
>
> +
>
> +static int virtio_mtu_set(struct rte_eth_dev *dev, uint16_t mtu)
>
> +{
>
> + struct virtio_hw *hw = dev->data->dev_private;
>
> + uint32_t ether_hdr_len = ETHER_HDR_LEN + VLAN_TAG_SIZE +
> + hw->
> vtnet_hdr_size;
>
> + uint32_t frame_size = mtu + ether_hdr_len;
>
> +
>
> + if (mtu < ETHER_MIN_MTU || frame_size >
> + VIRTIO_MAX_RX_PKTLEN ) {
>
> + PMD_INIT_LOG(ERR, "MTU should be between
> + %d and %d\
> n",
>
> + ETHER_MIN_MTU,
> + VIRTIO_MAX_RX_PKTLEN);
>
> + return -EINVAL;
>
> + }
>
> + return 0;
>
> +}
>
>
>
> /*
>
> * dev_ops for virtio, bare necessities for basic operation
>
> */
>
> @@ -677,7 +685,6 @@ static const struct eth_dev_ops virtio_eth_dev_ops
> = {
>
> .allmulticast_enable = virtio_dev_allmulticast_enable,
>
> .allmulticast_disable = virtio_dev_allmulticast_disable,
>
> + .mtu_set = virtio_mtu_set,
>
> .dev_infos_get = virtio_dev_info_get,
>
> .stats_get = virtio_dev_stats_get,
>
> .xstats_get = virtio_dev_xstats_get,
>
> --
>
> Please do let me know if this looks good to you all. Thanks
>
>
>
> --
>
> Regards,
>
> Souvik
>
>
>
> -----Original Message-----
> From: Kavanagh, Mark B [mailto:mark.b.kavanagh@intel.com]
> Sent: Friday, September 23, 2016 5:08 AM
> To: Yuanhan Liu <yuanhan.liu@linux.intel.com>; Stephen Hemminger
> <stephen@networkplumber.org>
> Cc: Dey, Souvik <sodey@sonusnet.com>; dev@dpdk.org
> Subject: RE: [PATCH v6] net/virtio: add set_mtu in virtio
>
>
>
> >Subject: Re: [PATCH v6] net/virtio: add set_mtu in virtio
>
> >
>
> >On Wed, Sep 21, 2016 at 06:45:05PM -0700, Stephen Hemminger wrote:
>
> >> On Thu, 22 Sep 2016 00:08:38 +0000
>
> >> "Dey, Souvik" <sodey@sonusnet.com> wrote:
>
> >>
>
> >> > Answers inline.
>
> >> >
>
> >> > --
>
> >> > Regards,
>
> >> > Souvik
>
> >> >
>
> >> > -----Original Message-----
>
> >> > From: Stephen Hemminger [mailto:stephen@networkplumber.org]
>
> >> > Sent: Wednesday, September 21, 2016 7:22 PM
>
> >> > To: Dey, Souvik <sodey@sonusnet.com>
>
> >> > Cc: mark.b.kavanagh@intel.com; yuanhan.liu@linux.intel.com;
>
> >> > dev@dpdk.org
>
> >> > Subject: Re: [PATCH v6] net/virtio: add set_mtu in virtio
>
> >> >
>
> >> > On Wed, 21 Sep 2016 19:11:47 -0400
>
> >> > Dey <sodey@sonusnet.com> wrote:
>
> >> >
>
> >> > >
>
> >> > > +
>
> >> > > +#define VLAN_TAG_SIZE 4 /* 802.3ac tag (not DMA'd) */
>
> >> > > +
>
> >> > > +static int virtio_mtu_set(struct rte_eth_dev *dev, uint16_t
> >> > > +mtu) {
>
> >> > > + struct rte_eth_dev_info dev_info;
>
> >> > > + uint32_t ether_hdr_len = ETHER_HDR_LEN + ETHER_CRC_LEN
> >> > > + +
> VLAN_TAG_SIZE;
>
> >> > > + uint32_t frame_size = mtu + ether_hdr_len;
>
> >> > > +
>
> >> > > + virtio_dev_info_get(dev, &dev_info);
>
> >> > > +
>
> >> > > + if (mtu < ETHER_MIN_MTU || frame_size >
> >> > > + dev_info.max_rx_pktlen)
> {
>
> >> > > + PMD_INIT_LOG(ERR, "MTU should be between %d and
> >> > > + %d\n",
>
> >> > > + ETHER_MIN_MTU,
>
> >> > > + (dev_info.max_rx_pktlen -
> ether_hdr_len));
>
> >> > > + return -EINVAL;
>
> >> > > + }
>
> >> > > + return 0;
>
> >> > > +}
>
> >> >
>
> >> > I am fine with the general idea of this patch but:
>
> >> > 1. Calling virtio_dev_info_get is needlessly wasteful when all
> >> > you want
>
> >> > is to access the max packet length. Since max_rx_pktlen is
> >> > always
>
> >> > VIRTIO_MAX_RX_PKTLEN, please just use that.
>
> >> > [Dey, Souvik] I am using the virtio_dev_info_get as in future
>
> >> > can/may support the
>
> >max_rx_pktlen as a variable to be set by the application. This will
>
> >keep the changes future proof. As we need to support till 65535
> >instead of
> 9728 as the linux does.
>
> >>
>
> >> Fine, then just dereference hw->rx_max_pktlen. Driver code
> >> can/should
>
> >> reference its own data directly.
>
> >
>
> >Dey, maybe you could just use VIRTIO_MAX_RX_PKTLEN here, like what
> >you
>
> >did in early versions.
>
> >
>
> >> >
>
> >> > 2. Defining VLAN_TAG_SIZE is irrelevant if doing vlan offload.
>
> >> > [Dey, Souvik] vlan offload is not mandatory. Se again still have
>
> >> > vlan being sent up to
>
> >the application. In that case we need to consider the vlan length in
> >the
> Ethernet size.
>
> >>
>
> >> The code needs to handle both vlan offload (or not), correctly. You
>
> >> are assuming the worst case here.
>
> >
>
> >I think we are fine here to assume worst case.
>
> >
>
> >> >
>
> >> > 3. Virtio doesn't insert CRC, therefore CRC_LEN is irrelevant
>
> >> > [Dey, Souvik] I am not sure of this. Mark commented earlier to
> >> > consider
> this length too.
>
> >Mark what do you suggest ?
>
> >>
>
> >> Actually, the thing that matters is the size of the merge rx buf
> >> header, not
> the CRC.
>
> >
>
> >Right.
>
>
>
> My comments were based on my experience with DPDK ethdev PMDs -
> Stephen and Yuanhan have much more experience with virtio, so I'd go with their suggestion.
>
>
>
> >
>
> > --yliu
>
> >>
>
> >> The patch is still buggy.
>
> >>
>
next prev parent reply other threads:[~2016-09-27 15:41 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-21 23:11 Dey
2016-09-21 23:22 ` Stephen Hemminger
2016-09-22 0:08 ` Dey, Souvik
2016-09-22 1:45 ` Stephen Hemminger
2016-09-22 2:29 ` Dey, Souvik
2016-09-23 7:53 ` Yuanhan Liu
2016-09-23 9:07 ` Kavanagh, Mark B
2016-09-23 15:17 ` Dey, Souvik
2016-09-26 3:21 ` Yuanhan Liu
2016-09-27 15:41 ` Dey, Souvik [this message]
2016-09-27 18:56 ` Stephen Hemminger
2016-09-27 20:44 ` Dey, Souvik
2016-09-27 23:11 ` Yuanhan Liu
2016-09-28 15:31 ` Dey, Souvik
2016-09-22 15:57 ` Stephen Hemminger
-- strict thread matches above, loose matches on Subject: below --
2016-09-21 21:10 Dey
2016-09-16 17:13 [dpdk-dev] [PATCH v5]net/virtio: add mtu set " souvikdey33
2016-09-22 13:56 ` [dpdk-dev] [PATCH v6] net/virtio: add set_mtu " Dey
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