[dpdk-dev] [PATCH 2/6] net/tap: add speed capabilities

Wiles, Keith keith.wiles at intel.com
Mon Mar 6 15:38:25 CET 2017


> On Mar 6, 2017, at 7:58 AM, Pascal Mazon <pascal.mazon at 6wind.com> wrote:
> 
> On Fri, 3 Mar 2017 15:27:12 +0000
> "Wiles, Keith" <keith.wiles at intel.com> wrote:
> 
>> 
>>> On Mar 3, 2017, at 3:46 AM, Pascal Mazon <pascal.mazon at 6wind.com>
>>> wrote:
>>> 
>>> Tap PMD is flexible, it supports any speed.
>>> 
>>> Signed-off-by: Pascal Mazon <pascal.mazon at 6wind.com>
>>> ---
>>> doc/guides/nics/features/tap.ini |  1 +
>>> drivers/net/tap/rte_eth_tap.c    | 35
>>> +++++++++++++++++++++++++++++++++++ 2 files changed, 36
>>> insertions(+)
>>> 
>>> diff --git a/doc/guides/nics/features/tap.ini
>>> b/doc/guides/nics/features/tap.ini index d9b47a003654..dad5a0561087
>>> 100644 --- a/doc/guides/nics/features/tap.ini
>>> +++ b/doc/guides/nics/features/tap.ini
>>> @@ -9,6 +9,7 @@ Jumbo frame          = Y
>>> Promiscuous mode     = Y
>>> Allmulticast mode    = Y
>>> Basic stats          = Y
>>> +Speed capabilities   = Y
>>> Unicast MAC filter   = Y
>>> Other kdrv           = Y
>>> ARMv7                = Y
>>> diff --git a/drivers/net/tap/rte_eth_tap.c
>>> b/drivers/net/tap/rte_eth_tap.c index 994c8be701c8..6670dfbb35ce
>>> 100644 --- a/drivers/net/tap/rte_eth_tap.c
>>> +++ b/drivers/net/tap/rte_eth_tap.c
>>> @@ -351,6 +351,40 @@ tap_dev_configure(struct rte_eth_dev *dev
>>> __rte_unused) return 0;
>>> }
>>> 
>>> +static uint32_t
>>> +tap_dev_speed_capa(void)
>>> +{
>>> +	uint32_t speed = pmd_link.link_speed;
>>> +	uint32_t capa = 0;
>>> +
>>> +	if (speed >= ETH_SPEED_NUM_10M)
>>> +		capa |= ETH_LINK_SPEED_10M;
>>> +	if (speed >= ETH_SPEED_NUM_100M)
>>> +		capa |= ETH_LINK_SPEED_100M;
>>> +	if (speed >= ETH_SPEED_NUM_1G)
>>> +		capa |= ETH_LINK_SPEED_1G;
>>> +	if (speed >= ETH_SPEED_NUM_5G)
>>> +		capa |= ETH_LINK_SPEED_2_5G;
>>> +	if (speed >= ETH_SPEED_NUM_5G)
>>> +		capa |= ETH_LINK_SPEED_5G;
>>> +	if (speed >= ETH_SPEED_NUM_10G)
>>> +		capa |= ETH_LINK_SPEED_10G;
>>> +	if (speed >= ETH_SPEED_NUM_20G)
>>> +		capa |= ETH_LINK_SPEED_20G;
>>> +	if (speed >= ETH_SPEED_NUM_25G)
>>> +		capa |= ETH_LINK_SPEED_25G;
>>> +	if (speed >= ETH_SPEED_NUM_40G)
>>> +		capa |= ETH_LINK_SPEED_40G;
>>> +	if (speed >= ETH_SPEED_NUM_50G)
>>> +		capa |= ETH_LINK_SPEED_50G;
>>> +	if (speed >= ETH_SPEED_NUM_56G)
>>> +		capa |= ETH_LINK_SPEED_56G;
>>> +	if (speed >= ETH_SPEED_NUM_100G)
>>> +		capa |= ETH_LINK_SPEED_100G;
>> 
>> In the real world the NIC may only support 50G an not say 10M, so in
>> that case this code would be wrong as it would set all of the speeds
>> up to 50G. I do not think the code should be changed, but I add a
>> comment to tell the developer the issue here. I do not want someone
>> copying the code and thinking is i correct for a real device.
>> 
> 
> That's true for actual hardware. But tap is completely virtual, so
> actually it could support any speed (it is limited by userland-kernel
> communication speed).
> 
> What speed would you rather have the tap PMD report as capable of?

This note was a very minor picky point and you can ignore my comment here. It is not worth the time to deal with and you have better things to do :-)

> 
> Best regards,
> Pascal
> 
>>> +
>>> +	return capa;
>>> +}
>>> +
>>> static void
>>> tap_dev_info(struct rte_eth_dev *dev, struct rte_eth_dev_info
>>> *dev_info) {
>>> @@ -363,6 +397,7 @@ tap_dev_info(struct rte_eth_dev *dev, struct
>>> rte_eth_dev_info *dev_info) dev_info->max_tx_queues =
>>> internals->nb_queues; dev_info->min_rx_bufsize = 0;
>>> 	dev_info->pci_dev = NULL;
>>> +	dev_info->speed_capa = tap_dev_speed_capa();
>>> }
>>> 
>>> static void
>>> -- 
>>> 2.8.0.rc0
>>> 
>> 
>> Regards,
>> Keith
>> 
> 

Regards,
Keith



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