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

["Zhang, Qi Z" <qi.z.zhang@intel.com>]

> -----Original Message-----
> From: Ilya Maximets [mailto:i.maximets@samsung.com]
> Sent: Tuesday, October 30, 2018 5:21 AM
> To: dev@dpdk.org
> Cc: Lu, Wenzhuo <wenzhuo.lu@intel.com>; Ananyev, Konstantin
> <konstantin.ananyev@intel.com>; Laurent Hardy
> <laurent.hardy@6wind.com>; Wei Dai <wei.dai@intel.com>;
> stable@dpdk.org; Zhang, Qi Z <qi.z.zhang@intel.com>; Thomas Monjalon
> <thomas.monjalon@6wind.com>; Yigit, Ferruh <ferruh.yigit@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?

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@dpdk.org
> >
> > Signed-off-by: Ilya Maximets <i.maximets@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;
> >