> -----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.
> >>>>
> >>>
> >>> vector width can be an option too, no objection there. But this is only
> >>> for
> >>> current configuration, so it can be a combination, we have now 5 types and
> >>> allocating space for 16.
> >>>
> >>
> >> correction: it can *not* be a combination
> >
> > I think we can merge the RX_VECTOR and TX_VECTOR together, use 6 bits for
> > vector
> > mode detail. And for vector width, the SSE, NEON name should indicates it ?
> >
> > I renamed the definitions to try to make things clear.
> >
> > 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
> ....
>
> Can any vector mode be combination of above, if not why use bitfields?
>
I use it as this to *set* ...
else if (pkt_burst == i40e_recv_scattered_pkts_vec_avx2)
options = BURST_VECTOR | BURST_AVX2 | BURST_SCATTERED;
else if (pkt_burst == i40e_recv_pkts_vec_avx2)
options = BURST_VECTOR | BURST_AVX2;
else if (pkt_burst == i40e_recv_scattered_pkts_vec)
options = BURST_VECTOR | BURST_SSE | BURST_SCATTERED;
else if (pkt_burst == i40e_recv_pkts_vec)
options = BURST_VECTOR | BURST_SSE;
Then *get* like this, since we reserve the bit group.
static void
burst_mode_options_display(uint64_t options)
{
uint64_t vec_mode = options & BURST_VECTOR_MODE_MASK;
uint64_t opt;
options &= ~BURST_VECTOR_MODE_MASK;
for (opt = 1; options != 0; opt <<= 1, options >>= 1) {
if (!(options & 1))
continue;
printf(" %s", rte_eth_burst_mode_option_name(opt));
if (opt == BURST_VECTOR)
printf("(%s)",
rte_eth_burst_mode_option_name(vec_mode));
}
}
>
> >
> > BURST_SCATTERED = (1 << 8),
> > BURST_BULK_ALLOC = (1 << 9),
> > BURST_NORMAL = (1 << 10),
>
> Not sure about this one, what is the difference between scalar?
>
Extract it from the function name and the debug message.
if (pkt_burst == i40e_recv_scattered_pkts)
options = BURST_SCALAR | BURST_SCATTERED;
else if (pkt_burst == i40e_recv_pkts_bulk_alloc)
options = BURST_SCALAR | BURST_BULK_ALLOC;
else if (pkt_burst == i40e_recv_pkts)
options = BURST_SCALAR | BURST_NORMAL;
> > BURST_SIMPLE = (1 << 11),
> > };
> >
> > /**
> > * Ethernet device RX/TX queue packet burst mode information structure.
> > * Used to retrieve information about packet burst mode setting.
> > */
> > struct rte_eth_burst_mode {
> > uint32_t per_queue_support:1; /**< Support to set per queue burst */
> >
> > uint64_t options;
> > };
> >
> > And three APIs:
> >
> > 1.
> > __rte_experimental
> > int rte_eth_rx_burst_mode_get(uint16_t port_id, uint16_t queue_id,
> > struct rte_eth_burst_mode *mode);
> >
> >
> > 2.
> > __rte_experimental
> > int rte_eth_tx_burst_mode_get(uint16_t port_id, uint16_t queue_id,
> > struct rte_eth_burst_mode *mode);
> >
> > 3.
> > __rte_experimental
> > const char *
> > rte_eth_burst_mode_option_name(uint64_t option);
>
> What about 'rte_eth_burst_mode_name()' ?
>
The "mode" scope is bigger than "mode_option", so I defined it as
"_mode_option_name()".
struct rte_eth_burst_mode {
uint32_t per_queue_support:1; /**< Support to set per queue burst */
uint64_t options;
};
> >
> >
> > PMD two ops:
> >
> > typedef void (*eth_burst_mode_get_t)(struct rte_eth_dev *dev,
> > uint16_t queue_id, struct rte_eth_burst_mode *mode);
> >
> > struct eth_dev_ops {
> > ...
> > eth_burst_mode_get_t rx_burst_mode_get; /**< Get RX burst mode */
> > eth_burst_mode_get_t tx_burst_mode_get; /**< Get TX burst mode */
> > ...
> > };
> >
