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

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

Hi Tonghao:
	Would you submit v4 with Ferruh' s fix and also do a rebase on next-net?
Thanks
Qi

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Ferruh Yigit
> Sent: Thursday, April 19, 2018 12:10 AM
> To: Tonghao Zhang <xiangxia.m.yue@gmail.com>
> Cc: Lu, Wenzhuo <wenzhuo.lu@intel.com>; Ananyev, Konstantin
> <konstantin.ananyev@intel.com>; Xing, Beilei <beilei.xing@intel.com>; Dai,
> Wei <wei.dai@intel.com>; dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v3 1/5] net/ixgbevf: set the inter-interrupt
> interval for EITR.
> 
> On 4/18/2018 2:01 AM, Tonghao Zhang wrote:
> > On Tue, Apr 17, 2018 at 7:00 PM, Ferruh Yigit <ferruh.yigit@intel.com>
> wrote:
> >> On 3/22/2018 1:01 PM, xiangxia.m.yue@gmail.com wrote:
> >>> From: Tonghao Zhang <xiangxia.m.yue@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@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. */
> >>>
> >>