[dpdk-dev] [PATCH v3 1/5] net/ixgbevf: set the inter-interrupt interval for EITR.

[Ferruh Yigit]

On 4/18/2018 2:01 AM, Tonghao Zhang wrote:
> On Tue, Apr 17, 2018 at 7:00 PM, Ferruh Yigit <ferruh.yigit at intel.com> wrote:
>> On 3/22/2018 1:01 PM, xiangxia.m.yue at gmail.com wrote:
>>> From: Tonghao Zhang <xiangxia.m.yue at gmail.com>
>>>
>>> Set EITR interval as default. This patch can improve the
>>> performance when we enable the rx-intrrupt to process the
>>> packets because we hope rx-intrrupt reduce CPU. For example,
>>> the 200us value of EITR makes the performance better with
>>> the low CPU.
>>>
>>> Users can configure the value of ITR via DPDK configuration.
>>>
>>> The default value of ITR is 500us, compatible with RSC of ixgbe PF,
>>> and next patch will use the default value.
>>>
>>> Signed-off-by: Tonghao Zhang <xiangxia.m.yue at gmail.com>
>>> ---
>>> v1 --> v2:
>>> use the configure file, for different user.
>>> suggested by Beilei Xing, http://dpdk.org/dev/patchwork/patch/32989
>>> ---
>>>  config/common_base               |  2 ++
>>>  drivers/net/ixgbe/ixgbe_ethdev.c |  7 +++++++
>>>  drivers/net/ixgbe/ixgbe_ethdev.h | 12 ++++++++++++
>>>  3 files changed, 21 insertions(+)
>>>
>>> diff --git a/config/common_base b/config/common_base
>>> index e74febe..2e9fded 100644
>>> --- a/config/common_base
>>> +++ b/config/common_base
>>> @@ -196,6 +196,8 @@ CONFIG_RTE_LIBRTE_IXGBE_DEBUG_DRIVER=n
>>>  CONFIG_RTE_LIBRTE_IXGBE_PF_DISABLE_STRIP_CRC=n
>>>  CONFIG_RTE_IXGBE_INC_VECTOR=y
>>>  CONFIG_RTE_LIBRTE_IXGBE_BYPASS=n
>>> +# interval up to 1024 us
>>> +CONFIG_RTE_LIBRTE_IXGBE_ITR_INTERVAL=-1
>>
>> I can understand this is to let user to ability to fine tune this value, the
>> down side is when number of these kind of tune parameters increased, it become
>> confusing and config options because less useful or perhaps useless.
>>
>> And overall we are trying to reduce config options we have.
>>
>> I can see there is already some default values in the header file, what do you
>> think removing the config option and go with default values defined in header?
> v2 used the default value in header, but for configuring it like as
> i40e option (CONFIG_RTE_LIBRTE_IXGBE_ITR_INTERVAL).
> so v3 makes some changes. These patches may have been applied. For
> reducing config option, should we do it in individual patches
> to fix the ixgbe/i40e option ?

Patches are still in Helin's tree, so this up to him how manage.
Since patches are not in main repo yet I would suggest making new version if
fits to Helin.

> 
>>>
>>>  #
>>>  # Compile burst-oriented I40E PMD driver
>>> diff --git a/drivers/net/ixgbe/ixgbe_ethdev.c b/drivers/net/ixgbe/ixgbe_ethdev.c
>>> index e67389f..495e72c 100644
>>> --- a/drivers/net/ixgbe/ixgbe_ethdev.c
>>> +++ b/drivers/net/ixgbe/ixgbe_ethdev.c
>>> @@ -5780,6 +5780,13 @@ static void ixgbevf_set_vfta_all(struct rte_eth_dev *dev, bool on)
>>>               if (vector_idx < base + intr_handle->nb_efd - 1)
>>>                       vector_idx++;
>>>       }
>>> +
>>> +     /* As RX queue setting above show, all queues use the vector 0.
>>> +      * Set only the ITR value of IXGBE_MISC_VEC_ID.
>>> +      */
>>> +     IXGBE_WRITE_REG(hw, IXGBE_VTEITR(IXGBE_MISC_VEC_ID),
>>> +                     ixgbe_calc_itr_interval(RTE_LIBRTE_IXGBE_ITR_INTERVAL)
>>> +                     | IXGBE_EITR_CNT_WDIS);
>>>  }
>>>
>>>  /**
>>> diff --git a/drivers/net/ixgbe/ixgbe_ethdev.h b/drivers/net/ixgbe/ixgbe_ethdev.h
>>> index 1db29bd..c779001 100644
>>> --- a/drivers/net/ixgbe/ixgbe_ethdev.h
>>> +++ b/drivers/net/ixgbe/ixgbe_ethdev.h
>>> @@ -58,6 +58,18 @@
>>>               IXGBE_EITR_ITR_INT_MASK)
>>>
>>>
>>> +#define IXGBE_QUEUE_ITR_INTERVAL_MAX 1024 /* 1024us */
>>> +#define IXGBE_QUEUE_ITR_INTERVAL_DEFAULT     500 /* 500us */
>>> +
>>> +static inline uint16_t
>>> +ixgbe_calc_itr_interval(int16_t interval)
>>> +{
>>> +     if (interval < 0 || interval > IXGBE_QUEUE_ITR_INTERVAL_MAX)
>>> +             interval = IXGBE_QUEUE_ITR_INTERVAL_DEFAULT;
>>> +
>>> +     return IXGBE_EITR_INTERVAL_US(interval);
>>> +}
>>> +
>>>  /* Loopback operation modes */
>>>  /* 82599 specific loopback operation types */
>>>  #define IXGBE_LPBK_82599_NONE   0x0 /* Default value. Loopback is disabled. */
>>>
>>