[dpdk-dev] [PATCH v3 2/2] net/virtio: add link speed devarg

[Ivan Dyukov]

Hi Tiwei,


12.02.2020 13:35, Tiwei Bie пишет:
> On Fri, Feb 07, 2020 at 02:25:26PM +0300, Ivan Dyukov wrote:
>> Some applications like pktgen use link_speed to calculate
>> transmit rate. It limits outcome traffic to hardcoded 10G.
>>
>> This patch adds link_speed devarg which allows to configure
>> link_speed of virtio device.
>>
>> Signed-off-by: Ivan Dyukov <i.dyukov at samsung.com>
>> ---
>>   doc/guides/nics/virtio.rst         |   7 ++
>>   drivers/net/virtio/virtio_ethdev.c | 101 ++++++++++++++++++++++++-----
>>   drivers/net/virtio/virtio_pci.h    |   1 +
>>   3 files changed, 92 insertions(+), 17 deletions(-)
> Maybe I missed something.. Why not enable the VIRTIO_NET_F_SPEED_DUPLEX
> support directly? When that feature is supported and negotiated,
> we will ignore this devarg?

VIRTIO_NET_F_SPEED_DUPLEX keeps tunable values. In case of kernel driver, they could be changed with ethtool. If a device is mapped to poll mode driver, I think, we can tune it with
dpdk devarg.  If devarg is not specified then negotiate VIRTIO_NET_F_SPEED_DUPLEX. This is my current vision of the feature, but I have to investigate it.

> If we want this devarg, it looks better to support it in virtio-user
> as well (most code is shared between virtio-PMD and virtio-user).

> Thanks!
> Tiwei
>