> -----Original Message-----
> From: Yigit, Ferruh
> Sent: Tuesday, September 10, 2019 23:03
> To: Wang, Haiyue <haiyue.w...@intel.com>; Richardson, Bruce
> <bruce.richard...@intel.com>
> Cc: Ray Kinsella <m...@ashroe.eu>; dev@dpdk.org; Sun, Chenmin
> <chenmin....@intel.com>
> Subject: Re: [dpdk-dev] [RFC v2 1/3] ethdev: add the API for getting trace
> information
>
> On 9/10/2019 3:19 PM, Wang, Haiyue wrote:
> >> -----Original Message-----
> >> From: Yigit, Ferruh
> >> Sent: Tuesday, September 10, 2019 17:15
> >> To: Wang, Haiyue <haiyue.w...@intel.com>; Richardson, Bruce
> >> <bruce.richard...@intel.com>
> >> Cc: Ray Kinsella <m...@ashroe.eu>; dev@dpdk.org; Sun, Chenmin
> >> <chenmin....@intel.com>
> >> Subject: Re: [dpdk-dev] [RFC v2 1/3] ethdev: add the API for getting trace
> >> information
> >>
> >> On 9/10/2019 9:37 AM, Wang, Haiyue wrote:
> >>>> -----Original Message-----
> >>>> From: Yigit, Ferruh
> >>>> Sent: Tuesday, September 10, 2019 16:07
> >>>> To: Wang, Haiyue <haiyue.w...@intel.com>; Richardson, Bruce
> >>>> <bruce.richard...@intel.com>
> >>>> Cc: Ray Kinsella <m...@ashroe.eu>; dev@dpdk.org; Sun, Chenmin
> >>>> <chenmin....@intel.com>
> >>>> Subject: Re: [dpdk-dev] [RFC v2 1/3] ethdev: add the API for getting
> >>>> trace information
> >>>>
> >>>> On 9/10/2019 5:36 AM, Wang, Haiyue wrote:
> >>>>> Thanks Ferruh, Bruce.
> >>>>>
> >>>>>> -----Original Message-----
> >>>>>> From: Yigit, Ferruh
> >>>>>> Sent: Monday, September 9, 2019 21:18
> >>>>>> To: Richardson, Bruce <bruce.richard...@intel.com>
> >>>>>> Cc: Wang, Haiyue <haiyue.w...@intel.com>; Ray Kinsella
> >>>>>> <m...@ashroe.eu>; dev@dpdk.org; Sun,
> >> Chenmin
> >>>>>> <chenmin....@intel.com>
> >>>>>> Subject: Re: [dpdk-dev] [RFC v2 1/3] ethdev: add the API for getting
> >>>>>> trace information
> >>>>>>
> >>>>>> On 9/9/2019 1:50 PM, Ferruh Yigit wrote:
> >>>>>>> On 9/9/2019 1:40 PM, Bruce Richardson wrote:
> >>>>>>>> On Mon, Sep 09, 2019 at 12:23:36PM +0100, Ferruh Yigit wrote:
> >>>>>>>>> On 9/7/2019 3:42 AM, Wang, Haiyue wrote:
> >>>>>>>>>>> -----Original Message-----
> >>>>>>>>>>> From: Yigit, Ferruh
> >>>>>>>>>>> Sent: Friday, September 6, 2019 22:22
> >>>>>>>>>>> To: Ray Kinsella <m...@ashroe.eu>; Wang, Haiyue
> >>>>>>>>>>> <haiyue.w...@intel.com>
> >>>>>>>>>>> Cc: dev@dpdk.org
> >>>>>>>>>>> Subject: Re: [dpdk-dev] [RFC v2 1/3] ethdev: add the API for
> >>>>>>>>>>> getting trace information
> >>>>>>>>>>>
> >>>>>>>>>>> On 8/13/2019 1:51 PM, Ray Kinsella wrote:
> >>>>>>>>>>>>
> >>>>>>>>>>>>
> >>>>>>>>>>>> On 13/08/2019 04:24, Stephen Hemminger wrote:
> >>>>>>>>>>>>> On Tue, 13 Aug 2019 11:06:10 +0800
> >>>>>>>>>>>>> Haiyue Wang <haiyue.w...@intel.com> wrote:
> >>>>>>>>>>>>>
> >>>>>>>>>>>>>> Enhance the PMD to support retrieving trace information like
> >>>>>>>>>>>>>> Rx/Tx burst selection etc.
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> Signed-off-by: Haiyue Wang <haiyue.w...@intel.com>
> >>>>>>>>>>>>>> ---
> >>>>>>>>>>>>>> lib/librte_ethdev/rte_ethdev.c | 18 ++++++++++++++++++
> >>>>>>>>>>>>>> lib/librte_ethdev/rte_ethdev.h | 9 +++++++++
> >>>>>>>>>>>>>> lib/librte_ethdev/rte_ethdev_core.h | 4 ++++
> >>>>>>>>>>>>>> 3 files changed, 31 insertions(+)
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> diff --git a/lib/librte_ethdev/rte_ethdev.c
> >>>>>>>>>>>>>> b/lib/librte_ethdev/rte_ethdev.c
> >>>>>>>>>>>>>> index 17d183e..6098fad 100644
> >>>>>>>>>>>>>> --- a/lib/librte_ethdev/rte_ethdev.c
> >>>>>>>>>>>>>> +++ b/lib/librte_ethdev/rte_ethdev.c
> >>>>>>>>>>>>>> @@ -4083,6 +4083,24 @@ rte_eth_tx_queue_info_get(uint16_t
> >>>>>>>>>>>>>> port_id, uint16_t queue_id,
> >>>>>>>>>>>>>> }
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> int
> >>>>>>>>>>>>>> +rte_eth_trace_info_get(uint16_t port_id, uint16_t queue_id,
> >>>>>>>>>>>>>> + enum rte_eth_trace type, char *buf, int
> >>>>>>>>>>>>>> sz)
> >>>>>>>>>>>
> >>>>>>>>>>> Better to use struct as argument instead of individual variables
> >>>>>>>>>>> because it is
> >>>>>>>>>>> easier to extend the struct later if needed.
> >>>>>>>>>>>
> >>>>>>>>>>>>>> +{
> >>>>>>>>>>>>>> + struct rte_eth_dev *dev;
> >>>>>>>>>>>>>> +
> >>>>>>>>>>>>>> + RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
> >>>>>>>>>>>>>> +
> >>>>>>>>>>>>>> + if (buf == NULL)
> >>>>>>>>>>>>>> + return -EINVAL;
> >>>>>>>>>>>>>> +
> >>>>>>>>>>>>>> + dev = &rte_eth_devices[port_id];
> >>>>>>>>>>>>>> +
> >>>>>>>>>>>>>> + RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->trace_info_get,
> >>>>>>>>>>>>>> -ENOTSUP);
> >>>>>>>>>>>>>> +
> >>>>>>>>>>>>>> + return dev->dev_ops->trace_info_get(dev, queue_id,
> >>>>>>>>>>>>>> type, buf, sz);
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> What if queueid is out of bounds?
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> The bigger problem is that this information is like a log
> >>>>>>>>>>>>> message
> >>>>>>>>>>>>> and unstructured, which makes it device specific and useless
> >>>>>>>>>>>>> for automation.
> >>>>>>>>>>>>
> >>>>>>>>>>>> IMHO - this is much better implemented as a capability bitfield,
> >>>>>>>>>>>> that
> >>>>>>>>>>>> can be queried.
> >>>>>>>>>>>
> >>>>>>>>>>> +1 to return the datapath capability as bitfield.
> >>>>>>>>>>>
> >>>>>>>>>>> Also +1 to have a new API,
> >>>>>>>>>>> - I am not sure about the API name, 'rte_eth_trace_info_get()',
> >>>>>>>>>>> can we find
> >>>>>>>>>>> something better instead of 'trace' there.
> >>>>>>>>>>> - I think we should limit this API only to get current datapath
> >>>>>>>>>>> configuration,
> >>>>>>>>>>> for clarity of the API don't return capability or not datapath
> >>>>>>>>>>> related config.
> >>>>>>>>>>>
> >>>>>>>>>>> Also this information not always supported in queue level, what
> >>>>>>>>>>> do you think
> >>>>>>>>>>> having ability to get this information in port level,
> >>>>>>>>>>> like this API can return a struct, which may have a field that
> >>>>>>>>>>> says if the
> >>>>>>>>>>> output is for queue or port, or this can be another bitfield,
> >>>>>>>>>>> what do you think?
> >>>>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>> #define RX_SCALAR (1ULL < 0)
> >>>>>>>>>> #define RX_VECTOR_AVX2 ...
> >>>>>>>>>
> >>>>>>>>> What about having RX_VECTOR value, later another bit group for the
> >>>>>>>>> details of
> >>>>>>>>> the vectorization:
> >>>>>>>>> SSE
> >>>>>>>>> AVX2
> >>>>>>>>> AVX512
> >>>>>>>>> NEON
> >>>>>>>>> ALTIVEC
> >>>>>>>>>
> >>>>>>>>> Since above options can exist together, what about using values for
> >>>>>>>>> them instead
> >>>>>>>>> of bitfields? Reserving 4 bits, 2^4 = 16, can be enough I think for
> >>>>>>>>> long term.
> >>>>>>>>>
> >>>>>>>> Rather than having named vector types, we just need to worry about
> >>>>>>>> the ones
> >>>>>>>> for the current architecture. Therefore I'd suggest just using vector
> >>>>>>>> widths, one bit each for 16B, 32B and 64B vector support. For
> >>>>>>>> supporting
> >>>>>>>> multiple values, 16 combinations is not enough for all the
> >>>>>>>> possibilities.
> >>>>>>>>
> >>>>>>>
> >>>>>
> >>>>> enum rte_eth_burst_mode_option {
> >>>>> BURST_SCALAR = (1 << 0),
> >>>>> BURST_VECTOR = (1 << 1),
> >>>>>
> >>>>> BURST_VECTOR_MODE_MASK = (0x3F << 2),
> >>>>> BURST_ALTIVEC = (1 << 2),
> >>>>> BURST_NEON = (2 << 2),
> >>>>> BURST_SSE = (3 << 2),
> >>>>> BURST_AVX2 = (4 << 2),
> >>>>> BURST_AVX512 = (5 << 2),
> >>>>
> >>>> Do we need to have bitfields for this, I was suggesting reserve 4 bits,
> >>>> bit 2-5
> >>>> (inclusive) and use their value:
> >>>>
> >>>> BURST_VECTOR_MODE_IDX = 2
> >>>> BURST_VECTOR_MODE_SIZE = 4
> >>>> BURST_VECTOR_MODE_MASK =
> >>>> ((1 << BURST_VECTOR_MODE_SIZE) - 1) << BURST_VECTOR_MODE_IDX
> >>>>
> >>>> vector_mode = (options & BURST_VECTOR_MODE_MASK) >> BURST_VECTOR_MODE_IDX
> >>>>
> >>>> if (vector_mode == 0) // BURST_SSE
> >>>> if (vector_mode == 1) // BURST_AVX2
> >>>> if (vector_mode == 2) // BURST_AVX512
> >>>> if (vector_mode == 3) // BURST_NEON
> >>> }
> >>>
> >>
> >> I can see how you intended use it, only they don't need to be bitfield and
> >> using
> >> with value saves bits.
> >> Also I think good to reserve some bits for future modes.
> >>
> >
> > I think I understand your 'value saves bits' concern now:
> >
> > What you mentioned value such as 1, 2, 3 has been *shifted* as new options:
> > (1 << 2),
> > (2 << 2), (3 << 2). The *shifted* value seems be easily for using, like,
> > you don't
> > need to re-define another enum like enum ...vector_mode { SSE, AVX2 } for
> > accessing.
> > And we can extract the vector mode easy: options & BURST_VECTOR_MODE_MASK,
> > no need to
> > shift right again for getting the pure number. And for displaying name, it
> > also should
> > be consistent:
> > ...
> > case RTE_ETH_BURST_VECTOR: return "Vector";
> > case RTE_ETH_BURST_ALTIVEC: return "AltiVec";
> > case RTE_ETH_BURST_NEON: return "Neon";
> >
>
> Yep, this is what I was suggesting, agree that bitwise is a little easier, and
> specially after having separate Rx/Tx APIs there are enough room in the
> variable, so ok with your suggestion.
> But please reserve some additional room future vectorisation modes, I would
> say
> overall 14 would be good, so first word can be for modes.
Got it, will change 4 bits for vector mode for saving the bit space.
