On Tue, Feb 28, 2023 at 12:04:53PM +0000, Ferruh Yigit wrote:
> On 2/28/2023 11:47 AM, Liu, Mingxia wrote:
>
> Comment moved down, please don't top post, it makes very hard to follow
> discussion.
>
> >> -----Original Message----- From: Ferruh Yigit <ferruh.yi...@amd.com>
> >> Sent: Tuesday, February 28, 2023 6:02 PM To: Liu, Mingxia
> >> <mingxia....@intel.com>; dev@dpdk.org; Xing, Beilei
> >> <beilei.x...@intel.com>; Zhang, Yuying <yuying.zh...@intel.com>
> >> Subject: Re: [PATCH v7 18/21] net/cpfl: add HW statistics
> >>
> >> On 2/28/2023 6:46 AM, Liu, Mingxia wrote:
> >>>
> >>>
> >>>> -----Original Message----- From: Ferruh Yigit <ferruh.yi...@amd.com>
> >>>> Sent: Tuesday, February 28, 2023 5:52 AM To: Liu, Mingxia
> >>>> <mingxia....@intel.com>; dev@dpdk.org; Xing, Beilei
> >>>> <beilei.x...@intel.com>; Zhang, Yuying <yuying.zh...@intel.com>
> >>>> Subject: Re: [PATCH v7 18/21] net/cpfl: add HW statistics
> >>>>
> >>>> On 2/16/2023 12:30 AM, Mingxia Liu wrote:
> >>>>> This patch add hardware packets/bytes statistics.
> >>>>>
> >>>>> Signed-off-by: Mingxia Liu <mingxia....@intel.com>
> >>>>
> >>>> <...>
> >>>>
> >>>>> +static int +cpfl_dev_stats_get(struct rte_eth_dev *dev, struct
> >>>>> rte_eth_stats +*stats) { + struct idpf_vport *vport = +
> >>>>> (struct idpf_vport *)dev->data->dev_private; + struct
> >>>>> virtchnl2_vport_stats *pstats = NULL; + int ret; + + ret =
> >>>>> idpf_vc_stats_query(vport, &pstats); + if (ret == 0) { +
> >>>>> uint8_t crc_stats_len = (dev->data- dev_conf.rxmode.offloads & +
> >>>>> RTE_ETH_RX_OFFLOAD_KEEP_CRC) ?
> >>>> 0 :
> >>>>> + RTE_ETHER_CRC_LEN; + +
> >>>>> idpf_vport_stats_update(&vport->eth_stats_offset, pstats); +
> >>>>> stats->ipackets = pstats->rx_unicast + pstats->rx_multicast + +
> >>>>> pstats->rx_broadcast - pstats->rx_discards; +
> >>>>> stats->opackets = pstats->tx_broadcast + pstats->tx_multicast
> >>>> +
> >>>>> + pstats->tx_unicast;
> >>>>> + stats->imissed = pstats->rx_discards; +
> >>>>> stats->oerrors = pstats->tx_errors + pstats->tx_discards; +
> >>>>> stats->ibytes = pstats->rx_bytes; + stats->ibytes -=
> >>>>> stats->ipackets * crc_stats_len; + stats->obytes =
> >>>>> pstats->tx_bytes; + + dev->data->rx_mbuf_alloc_failed =
> >>>>> +cpfl_get_mbuf_alloc_failed_stats(dev);
> >>>>
> >>>> 'dev->data->rx_mbuf_alloc_failed' is also used by telemetry,
> >>>> updating here only in stats_get() will make it wrong for telemetry.
> >>>>
> >>>> Is it possible to update 'dev->data->rx_mbuf_alloc_failed' whenever
> >>>> alloc failed? (alongside 'rxq->rx_stats.mbuf_alloc_failed').
> >>> [Liu, Mingxia] As I know, rte_eth_dev_data is not a public structure
> >>> provided
> >> to user, user need to access through rte_ethdev APIs.
> >>> Because we already put rx and tx burst func to common/idpf which has
> >>> no
> >> dependcy with ethdev lib. If I update
> >> "dev->data->rx_mbuf_alloc_failed"
> >>> when allocate mbuf fails, it will break the design of our common/idpf
> >> interface to net/cpfl or net.idpf.
> >>>
> >>> And I didn't find any reference of 'dev->data->rx_mbuf_alloc_failed'
> >>> in lib
> >> code.
> >>>
> >>
> >> Please check 'eth_dev_handle_port_info()' function. As I said this is
> >> used by telemetry, not directly exposed to the user.
> >>
> >> I got the design concern, perhaps you can put a brief limitation to
> >> the driver documentation.
> >>
> > OK, got it.
> >
> > As our previous design did have flaws. And if we don't want to affect
> > correctness of telemetry, we have to redesign the idpf common module
> > code, which means a lot of work to do, so can we lower the priority of
> > this issue?
> >
> I don't believe this is urgent, can you but a one line limitation to the
> documentation for now, and fix it later?
>
> And for the fix, updating 'dev->data->rx_mbuf_alloc_failed' where ever
> 'rxq->rx_stats.mbuf_alloc_failed' updated is easy, although you may need
> to store 'dev->data' in rxq struct for this.
>
> But, I think it is also fair to question the assumption telemetry has
> that 'rx_mbuf_alloc_fail' is always available data, and consider moving
> it to the 'eth_dev_handle_port_stats()' handler. +Bruce for comment.
>
That's not really a telemetry assumption, it's one from the stats,
structure. Telemetry just outputs the contents of data reported by ethdev
stats, and rx_nombuf is just one of those fields.
/Bruce
