Re: [dpdk-dev] [PATCH v2] net/virtio: add link speed tuning

[Ivan Dyukov <i.dyukov@samsung.com>]

Hi Maxime,
Thank you for comments.


13.12.2019 17:59, Maxime Coquelin пишет:
> Hi Ivan,
>
> On 12/13/19 3:44 PM, Ivan Dyukov wrote:
>> Some applications like pktgen use link_speed to calculate transmit
>> rate. It limits outcome traffic to hardcoded 10G.
>>
>> This patch makes link_speed configurable at compile time.
>>
>> Signed-off-by: Ivan Dyukov <i.dyukov@samsung.com>
>> ---
>>   config/common_base                 |  1 +
>>   config/meson.build                 |  1 +
>>   drivers/net/vhost/rte_eth_vhost.c  |  2 +-
>>   drivers/net/virtio/virtio_ethdev.c | 20 ++++++++++++++++----
>>   4 files changed, 19 insertions(+), 5 deletions(-)
>>
>> diff --git a/config/common_base b/config/common_base
>> index 7dec7ed45..8589ca4ec 100644
>> --- a/config/common_base
>> +++ b/config/common_base
>> @@ -433,6 +433,7 @@ CONFIG_RTE_LIBRTE_AVP_DEBUG_BUFFERS=n
>>   # Compile burst-oriented VIRTIO PMD driver
>>   #
>>   CONFIG_RTE_LIBRTE_VIRTIO_PMD=y
>> +CONFIG_RTE_LIBRTE_VIRTIO_LINK_SPEED=10000
>>   CONFIG_RTE_LIBRTE_VIRTIO_DEBUG_RX=n
>>   CONFIG_RTE_LIBRTE_VIRTIO_DEBUG_TX=n
>>   CONFIG_RTE_LIBRTE_VIRTIO_DEBUG_DUMP=n
>> diff --git a/config/meson.build b/config/meson.build
>> index 364a8d739..78c30f334 100644
>> --- a/config/meson.build
>> +++ b/config/meson.build
>> @@ -202,6 +202,7 @@ dpdk_conf.set('RTE_LIBEAL_USE_HPET', get_option('use_hpet'))
>>   dpdk_conf.set('RTE_MAX_VFIO_GROUPS', 64)
>>   dpdk_conf.set('RTE_DRIVER_MEMPOOL_BUCKET_SIZE_KB', 64)
>>   dpdk_conf.set('RTE_LIBRTE_DPAA2_USE_PHYS_IOVA', true)
>> +dpdk_conf.set('RTE_LIBRTE_VIRTIO_LINK_SPEED', 10000)
>>   
>>   
>>   compile_time_cpuflags = []
>> diff --git a/drivers/net/vhost/rte_eth_vhost.c b/drivers/net/vhost/rte_eth_vhost.c
>> index 46f01a7f4..38eaa5955 100644
>> --- a/drivers/net/vhost/rte_eth_vhost.c
>> +++ b/drivers/net/vhost/rte_eth_vhost.c
>> @@ -115,7 +115,7 @@ static struct internal_list_head internal_list =
>>   static pthread_mutex_t internal_list_lock = PTHREAD_MUTEX_INITIALIZER;
>>   
>>   static struct rte_eth_link pmd_link = {
>> -		.link_speed = 10000,
>> +		.link_speed = RTE_LIBRTE_VIRTIO_LINK_SPEED,
>>   		.link_duplex = ETH_LINK_FULL_DUPLEX,
>>   		.link_status = ETH_LINK_DOWN
>>   };
>> diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
>> index 044eb10a7..948091cc2 100644
>> --- a/drivers/net/virtio/virtio_ethdev.c
>> +++ b/drivers/net/virtio/virtio_ethdev.c
>> @@ -2371,7 +2371,7 @@ virtio_dev_link_update(struct rte_eth_dev *dev, __rte_unused int wait_to_complet
>>   
>>   	memset(&link, 0, sizeof(link));
>>   	link.link_duplex = ETH_LINK_FULL_DUPLEX;
>> -	link.link_speed  = ETH_SPEED_NUM_10G;
>> +	link.link_speed  = RTE_LIBRTE_VIRTIO_LINK_SPEED;
>>   	link.link_autoneg = ETH_LINK_FIXED;
>>   
>>   	if (!hw->started) {
>> @@ -2426,9 +2426,21 @@ virtio_dev_info_get(struct rte_eth_dev *dev, struct rte_eth_dev_info *dev_info)
>>   {
>>   	uint64_t tso_mask, host_features;
>>   	struct virtio_hw *hw = dev->data->dev_private;
>> -
>> -	dev_info->speed_capa = ETH_LINK_SPEED_10G; /* fake value */
>> -
>> +#if RTE_LIBRTE_VIRTIO_LINK_SPEED == ETH_LINK_SPEED_20G
>> +	dev_info->speed_capa = ETH_LINK_SPEED_20G;
>> +#elif RTE_LIBRTE_VIRTIO_LINK_SPEED == ETH_SPEED_NUM_25G
>> +	dev_info->speed_capa = ETH_LINK_SPEED_25G;
>> +#elif RTE_LIBRTE_VIRTIO_LINK_SPEED == ETH_SPEED_NUM_40G
>> +	dev_info->speed_capa = ETH_LINK_SPEED_40G;
>> +#elif RTE_LIBRTE_VIRTIO_LINK_SPEED == ETH_SPEED_NUM_50G
>> +	dev_info->speed_capa = ETH_LINK_SPEED_50G;
>> +#elif RTE_LIBRTE_VIRTIO_LINK_SPEED == ETH_SPEED_NUM_56G
>> +	dev_info->speed_capa = ETH_LINK_SPEED_56G;
>> +#elif RTE_LIBRTE_VIRTIO_LINK_SPEED == ETH_SPEED_NUM_100G
>> +	dev_info->speed_capa = ETH_LINK_SPEED_100G;
>> +#else
>> +	dev_info->speed_capa = ETH_LINK_SPEED_10G;
>> +#endif
>>   	dev_info->max_rx_queues =
>>   		RTE_MIN(hw->max_queue_pairs, VIRTIO_MAX_RX_QUEUES);
>>   	dev_info->max_tx_queues =
>>
> I think we may need toi extend the Virtio specification so that the
> device can advertise the link speed.
I agree. It will be more flexible solution, but it will require another 
effort. I'll evalutate virtio spec and check if it's suitable for such 
changes.
> Problem with your proposal is that it is build time only, so:
> 1. It won't be configurable when using distros DPDK package.
> 2. All the Virtio devices on a system will have the same value
Current implementation is same. Nothing is broken here. :)
> While any Virtio spec update introduce link speed support, wouldn't it
> be preferable to have this as a devarg?
For my case, compile time configuration is ok. Let me prepare solution 
with devarg then we can choose the better one.
> Thanks,
> Maxime

Best regards,

Ivan.