From: Ilya Maximets <i.maximets@samsung.com>
To: "Zhang, Qi Z" <qi.z.zhang@intel.com>, "dev@dpdk.org" <dev@dpdk.org>
Cc: "Lu, Wenzhuo" <wenzhuo.lu@intel.com>,
"Ananyev, Konstantin" <konstantin.ananyev@intel.com>,
Laurent Hardy <laurent.hardy@6wind.com>,
"Dai, Wei" <wei.dai@intel.com>,
"stable@dpdk.org" <stable@dpdk.org>
Subject: Re: [dpdk-stable] [dpdk-dev] [PATCH] net/ixgbe: fix busy polling while fiber link update
Date: Mon, 10 Sep 2018 18:08:49 +0300 [thread overview]
Message-ID: <20180910150708eucas1p220c16857c4277b311ddc000b9337d9cb~TEk8KngQJ1365413654eucas1p2a@eucas1p2.samsung.com> (raw)
In-Reply-To: <039ED4275CED7440929022BC67E706115327FA5E@SHSMSX103.ccr.corp.intel.com>
On 04.09.2018 09:08, Zhang, Qi Z wrote:
> Hi Ilya:
>
>> -----Original Message-----
>> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Ilya Maximets
>> Sent: Friday, August 31, 2018 8:40 PM
>> To: dev@dpdk.org
>> Cc: Lu, Wenzhuo <wenzhuo.lu@intel.com>; Ananyev, Konstantin
>> <konstantin.ananyev@intel.com>; Laurent Hardy
>> <laurent.hardy@6wind.com>; Dai, Wei <wei.dai@intel.com>; Ilya Maximets
>> <i.maximets@samsung.com>; stable@dpdk.org
>> Subject: [dpdk-dev] [PATCH] net/ixgbe: fix busy polling while fiber link update
>>
>> 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.
>
> Does that mean we will block the interrupt thread for 3 seconds?
Three times for one second. Other work could be scheduled between.
IMHO, it's much better than blocking usual caller for 3 seconds.
> Also, can we guarantee there will not be any race condition if we call ixgbe_setup_link at another thread, the base code API is not assumed to be thread-safe as I know.
The only user of 'ixgbe_setup_link' is 'ixgbe_dev_start', but it could be
called only if device stopped. 'ixgbe_dev_stop' cancels the alarm.
Race with 'link_update' avoided by 'IXGBE_FLAG_NEED_LINK_CONFIG' flag.
>
> Regards
> Qi
>
>>
>> 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;
>> --
>> 2.17.1
>
next prev parent reply other threads:[~2018-09-10 15:07 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20180831123824eucas1p1cd2981c716c4764703e24c3eeb4d33c7@eucas1p1.samsung.com>
2018-08-31 12:39 ` [dpdk-stable] " Ilya Maximets
2018-09-04 6:08 ` [dpdk-stable] [dpdk-dev] " Zhang, Qi Z
2018-09-10 15:08 ` Ilya Maximets [this message]
2018-09-12 6:49 ` Zhang, Qi Z
2018-09-12 8:05 ` Ilya Maximets
2018-09-12 8:28 ` Zhang, Qi Z
2018-09-21 14:25 ` Zhang, Qi Z
2018-10-03 7:43 ` Ilya Maximets
2018-10-09 10:22 ` Zhao1, Wei
2018-10-11 9:56 ` Zhao1, Wei
2018-10-11 10:26 ` Ilya Maximets
2018-10-11 12:21 ` Laurent Hardy
2018-10-12 7:36 ` Zhao1, Wei
2018-10-15 10:43 ` Laurent Hardy
2018-10-16 8:29 ` Zhao1, Wei
2018-10-12 9:19 ` Zhao1, Wei
2018-10-12 10:14 ` Ilya Maximets
2018-10-15 3:03 ` Zhao1, Wei
2018-10-15 8:40 ` Ilya Maximets
2018-10-16 8:59 ` Zhao1, Wei
2018-10-30 10:20 ` [dpdk-stable] " Ilya Maximets
2018-11-01 15:45 ` Zhang, Qi Z
2018-11-01 16:05 ` Ilya Maximets
[not found] ` <CGME20181101160505eucas1p1fcf268f3febaa80dcbb3e573b2fc2c68@eucas1p1.samsung.com>
2018-11-01 16:04 ` [dpdk-stable] [PATCH v2] " Ilya Maximets
2018-11-02 13:49 ` Zhang, Qi Z
2018-11-07 15:52 ` [dpdk-stable] [dpdk-dev] " Burakov, Anatoly
2018-11-08 10:27 ` Ilya Maximets
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