[dpdk-stable] [PATCH] net/ixgbe: fix busy polling while fiber link update

[Ilya Maximets]

On 01.11.2018 18:45, Zhang, Qi Z wrote:
> 
> 
>> -----Original Message-----
>> From: Ilya Maximets [mailto:i.maximets at samsung.com]
>> Sent: Tuesday, October 30, 2018 5:21 AM
>> To: dev at dpdk.org
>> Cc: Lu, Wenzhuo <wenzhuo.lu at intel.com>; Ananyev, Konstantin
>> <konstantin.ananyev at intel.com>; Laurent Hardy
>> <laurent.hardy at 6wind.com>; Wei Dai <wei.dai at intel.com>;
>> stable at dpdk.org; Zhang, Qi Z <qi.z.zhang at intel.com>; Thomas Monjalon
>> <thomas.monjalon at 6wind.com>; Yigit, Ferruh <ferruh.yigit at intel.com>
>> Subject: Re: [PATCH] net/ixgbe: fix busy polling while fiber link update
>>
>> Any more thoughts on that fix?
>> Or is there any chance for it to be accepted?
> 
> Would you rebase to dpdk-next-net-intel?

Done.

> Thanks
> Qi
> 
>>
>> Best regards, Ilya Maximets.
>>
>> On 31.08.2018 15:39, Ilya Maximets wrote:
>>> If the multispeed fiber link is in DOWN state, ixgbe_setup_link could
>>> take around a second of busy polling. This is highly inconvenient for
>>> the case where single thread periodically checks the link statuses.
>>> For example, OVS main thread periodically updates the link statuses
>>> and hangs for a really long time busy waiting on ixgbe_setup_link()
>>> for a DOWN fiber ports. For case with 3 down ports it hangs for a 3
>>> seconds and unable to do anything including packet processing.
>>> Fix that by shifting that workaround to a separate thread by alarm
>>> handler that will try to set up link if it is DOWN.
>>>
>>> Fixes: c12d22f65b13 ("net/ixgbe: ensure link status is updated")
>>> CC: stable at dpdk.org
>>>
>>> Signed-off-by: Ilya Maximets <i.maximets at samsung.com>
>>> ---
>>>  drivers/net/ixgbe/ixgbe_ethdev.c | 43
>>> ++++++++++++++++++++++++--------
>>>  1 file changed, 32 insertions(+), 11 deletions(-)
>>>
>>> diff --git a/drivers/net/ixgbe/ixgbe_ethdev.c
>>> b/drivers/net/ixgbe/ixgbe_ethdev.c
>>> index 26b192737..a33b9a6e8 100644
>>> --- a/drivers/net/ixgbe/ixgbe_ethdev.c
>>> +++ b/drivers/net/ixgbe/ixgbe_ethdev.c
>>> @@ -221,6 +221,8 @@ static int ixgbe_dev_interrupt_action(struct
>> rte_eth_dev *dev,
>>>  				      struct rte_intr_handle *handle);  static void
>>> ixgbe_dev_interrupt_handler(void *param);  static void
>>> ixgbe_dev_interrupt_delayed_handler(void *param);
>>> +static void ixgbe_dev_setup_link_alarm_handler(void *param);
>>> +
>>>  static int ixgbe_add_rar(struct rte_eth_dev *dev, struct ether_addr
>> *mac_addr,
>>>  			 uint32_t index, uint32_t pool);
>>>  static void ixgbe_remove_rar(struct rte_eth_dev *dev, uint32_t
>>> index); @@ -2791,6 +2793,8 @@ ixgbe_dev_stop(struct rte_eth_dev *dev)
>>>
>>>  	PMD_INIT_FUNC_TRACE();
>>>
>>> +	rte_eal_alarm_cancel(ixgbe_dev_setup_link_alarm_handler, dev);
>>> +
>>>  	/* disable interrupts */
>>>  	ixgbe_disable_intr(hw);
>>>
>>> @@ -3969,6 +3973,25 @@ ixgbevf_check_link(struct ixgbe_hw *hw,
>> ixgbe_link_speed *speed,
>>>  	return ret_val;
>>>  }
>>>
>>> +static void
>>> +ixgbe_dev_setup_link_alarm_handler(void *param) {
>>> +	struct rte_eth_dev *dev = (struct rte_eth_dev *)param;
>>> +	struct ixgbe_hw *hw =
>> IXGBE_DEV_PRIVATE_TO_HW(dev->data->dev_private);
>>> +	struct ixgbe_interrupt *intr =
>>> +		IXGBE_DEV_PRIVATE_TO_INTR(dev->data->dev_private);
>>> +	u32 speed;
>>> +	bool autoneg = false;
>>> +
>>> +	speed = hw->phy.autoneg_advertised;
>>> +	if (!speed)
>>> +		ixgbe_get_link_capabilities(hw, &speed, &autoneg);
>>> +
>>> +	ixgbe_setup_link(hw, speed, true);
>>> +
>>> +	intr->flags &= ~IXGBE_FLAG_NEED_LINK_CONFIG; }
>>> +
>>>  /* return 0 means link status changed, -1 means not changed */  int
>>> ixgbe_dev_link_update_share(struct rte_eth_dev *dev, @@ -3981,9
>>> +4004,7 @@ ixgbe_dev_link_update_share(struct rte_eth_dev *dev,
>>>  		IXGBE_DEV_PRIVATE_TO_INTR(dev->data->dev_private);
>>>  	int link_up;
>>>  	int diag;
>>> -	u32 speed = 0;
>>>  	int wait = 1;
>>> -	bool autoneg = false;
>>>
>>>  	memset(&link, 0, sizeof(link));
>>>  	link.link_status = ETH_LINK_DOWN;
>>> @@ -3993,13 +4014,8 @@ ixgbe_dev_link_update_share(struct
>> rte_eth_dev
>>> *dev,
>>>
>>>  	hw->mac.get_link_status = true;
>>>
>>> -	if ((intr->flags & IXGBE_FLAG_NEED_LINK_CONFIG) &&
>>> -		ixgbe_get_media_type(hw) == ixgbe_media_type_fiber) {
>>> -		speed = hw->phy.autoneg_advertised;
>>> -		if (!speed)
>>> -			ixgbe_get_link_capabilities(hw, &speed, &autoneg);
>>> -		ixgbe_setup_link(hw, speed, true);
>>> -	}
>>> +	if (intr->flags & IXGBE_FLAG_NEED_LINK_CONFIG)
>>> +		return rte_eth_linkstatus_set(dev, &link);
>>>
>>>  	/* check if it needs to wait to complete, if lsc interrupt is enabled */
>>>  	if (wait_to_complete == 0 || dev->data->dev_conf.intr_conf.lsc != 0)
>>> @@ -4017,11 +4033,14 @@ ixgbe_dev_link_update_share(struct
>> rte_eth_dev *dev,
>>>  	}
>>>
>>>  	if (link_up == 0) {
>>> -		intr->flags |= IXGBE_FLAG_NEED_LINK_CONFIG;
>>> +		if (ixgbe_get_media_type(hw) == ixgbe_media_type_fiber) {
>>> +			intr->flags |= IXGBE_FLAG_NEED_LINK_CONFIG;
>>> +			rte_eal_alarm_set(10,
>>> +				ixgbe_dev_setup_link_alarm_handler, dev);
>>> +		}
>>>  		return rte_eth_linkstatus_set(dev, &link);
>>>  	}
>>>
>>> -	intr->flags &= ~IXGBE_FLAG_NEED_LINK_CONFIG;
>>>  	link.link_status = ETH_LINK_UP;
>>>  	link.link_duplex = ETH_LINK_FULL_DUPLEX;
>>>
>>> @@ -5128,6 +5147,8 @@ ixgbevf_dev_stop(struct rte_eth_dev *dev)
>>>
>>>  	PMD_INIT_FUNC_TRACE();
>>>
>>> +	rte_eal_alarm_cancel(ixgbe_dev_setup_link_alarm_handler, dev);
>>> +
>>>  	ixgbevf_intr_disable(dev);
>>>
>>>  	hw->adapter_stopped = 1;
>>>