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From: "Wang, Haiyue" <haiyue.wang@intel.com>
To: Jerin Jacob <jerinjacobk@gmail.com>
Cc: Thomas Monjalon <thomas@monjalon.net>,
	"Yigit, Ferruh" <ferruh.yigit@intel.com>, dpdk-dev <dev@dpdk.org>,
	"Ye, Xiaolong" <xiaolong.ye@intel.com>,
	"Kinsella, Ray" <ray.kinsella@intel.com>,
	"Iremonger, Bernard" <bernard.iremonger@intel.com>,
	"Sun, Chenmin" <chenmin.sun@intel.com>,
	Andrew Rybchenko <arybchenko@solarflare.com>,
	"Slava Ovsiienko" <viacheslavo@mellanox.com>,
	Stephen Hemminger <stephen@networkplumber.org>,
	David Marchand <david.marchand@redhat.com>,
	Jerin Jacob <jerinj@marvell.com>
Subject: Re: [dpdk-dev] [PATCH v4 1/4] ethdev: add the API for getting burst mode information
Date: Tue, 29 Oct 2019 05:42:11 +0000	[thread overview]
Message-ID: <E3B9F2FDCB65864C82CD632F23D8AB8773D8C176@shsmsx102.ccr.corp.intel.com> (raw)
In-Reply-To: <CALBAE1Mg_qxabd9K8JpKZNaNzkbJSFnaZHy1HLJw7V3OBBNtGA@mail.gmail.com>

> -----Original Message-----
> From: Jerin Jacob <jerinjacobk@gmail.com>
> Sent: Tuesday, October 29, 2019 13:20
> To: Wang, Haiyue <haiyue.wang@intel.com>
> Cc: Thomas Monjalon <thomas@monjalon.net>; Yigit, Ferruh <ferruh.yigit@intel.com>; dpdk-dev
> <dev@dpdk.org>; Ye, Xiaolong <xiaolong.ye@intel.com>; Kinsella, Ray <ray.kinsella@intel.com>;
> Iremonger, Bernard <bernard.iremonger@intel.com>; Sun, Chenmin <chenmin.sun@intel.com>; Andrew
> Rybchenko <arybchenko@solarflare.com>; Slava Ovsiienko <viacheslavo@mellanox.com>; Stephen Hemminger
> <stephen@networkplumber.org>; David Marchand <david.marchand@redhat.com>; Jerin Jacob
> <jerinj@marvell.com>
> Subject: Re: [dpdk-dev] [PATCH v4 1/4] ethdev: add the API for getting burst mode information
> 
> On Tue, Oct 29, 2019 at 10:14 AM Wang, Haiyue <haiyue.wang@intel.com> wrote:
> >
> > > -----Original Message-----
> > > From: Jerin Jacob <jerinjacobk@gmail.com>
> > > Sent: Tuesday, October 29, 2019 11:38
> > > To: Wang, Haiyue <haiyue.wang@intel.com>
> > > Cc: Thomas Monjalon <thomas@monjalon.net>; Yigit, Ferruh <ferruh.yigit@intel.com>; dpdk-dev
> > > <dev@dpdk.org>; Ye, Xiaolong <xiaolong.ye@intel.com>; Kinsella, Ray <ray.kinsella@intel.com>;
> > > Iremonger, Bernard <bernard.iremonger@intel.com>; Sun, Chenmin <chenmin.sun@intel.com>; Andrew
> > > Rybchenko <arybchenko@solarflare.com>; Slava Ovsiienko <viacheslavo@mellanox.com>; Stephen
> Hemminger
> > > <stephen@networkplumber.org>; David Marchand <david.marchand@redhat.com>; Jerin Jacob
> > > <jerinj@marvell.com>
> > > Subject: Re: [dpdk-dev] [PATCH v4 1/4] ethdev: add the API for getting burst mode information
> > >
> > > > > > > struct rte_eth_burst_mode {
> > > > > > >         uint64_t options;
> > > > > > >         char dev_specific[128]; /* PMD has specific burst mode information */
> > > > > > > };
> > > > > >
> > > > > > I really don't see how we can have generic flags.
> > > > > > The flags which are proposed are just matching
> > > > > > the functions implemented in Intel PMDs.
> > > > > > And this is a complicate solution.
> > > > > > Why not just returning a name for the selected Rx/Tx mode?
> > > > >
> > > > > +1 only for the name
> > > > >
> > > > > Let me clarify my earlier proposal:
> > > > >
> > > > > 1) The public ethdev API should return only "string" i.e the flags
> > > > > SHOULD NOT be exposed as ethdev API
> > > > > i.e
> > > > > int rte_eth_tx_burst_mode_name(uint16_t port_id, uint16_t queue_id, char *name);
> > > > >
> > > > > 2) The PMD interface  to the common code can be following
> > > > >
> > > > >  struct eth_pmd_burst_mode {
> > > > >         uint64_t options;
> > > > >          char name[128]; /* PMD specific burst mode information */
> > > > > };
> > > > >
> > > > > typedef int (*eth_burst_mode_get_t)(struct rte_eth_dev *dev,
> > > > >         uint16_t queue_id, struct eth_burst_mode *mode)
> > > > >
> > > > > 3) The implementation of rte_eth_tx_burst_mode_name() shall do optons
> > > > > flag to string converion(again internal to common code implemetation)
> > > > > and concatenate with eth_pmd_burst_mode::name
> > > > >
> > > > > This would help to reuse some of the flags to name conversion logic
> > > > > across all PMDs.
> > > > > And PMD are free to return  eth_pmd_burst_mode::options as zero in
> > > > > that case final
> > > > > string only be eth_pmd_burst_mode::name.
> > > > >
> > > >
> > > > In fact, 'rte_eth_burst_mode_option_name' for single option, not
> > > > for struct eth_pmd_burst_mode::option[s]. Need loop to display them.
> > >
> > > I see two issues with the flag approach in public API(Internally for
> > > common code it fine to avoid code duplication)
> > >
> > > 1) We can not standardize all flags when it comes to HW specific
> > > details. We should NOT pollute public API with HW specific details.
> >
> > Currently, no detail to HW NIC specific.
> 
> Yes. What if I want to add a "String" they represent a specific mode of PMD,
> so that I know what mode PMD really runs.
> It is not worth adding a flag for that in public API for HW specific notion.
> That's the problem.
> 
> >
> > > 2) There is a danger if application starts taking any action based on
> > > flags. It should be only for display purpose so in that case public
> > > API should be the string to avoid misuse of the API(eventually the app
> > > will fail on some PMD
> > > if it takes any action based on the flag)
> >
> > These flags are *read only* for information. Can't image how to hack DPDK. ;-)
> 
> To clarify:
> If we expose flag say RTE_ETH_BURST_SIMPLE then the application can take
> some action based on
> if (flag == RTE_ETH_BURST_SIMPLE)
>     do_some_thing();
> 
> If the purpose is ONLY for "display" as info then exposing as the string will
> enable to NOT standardize i.e application can never check based on
> the string name(as it is not standardized) hence no danger.
> 
> So what is the purpose of this API? Just display or are you expecting
> the application can do any action based on this?

Oh, I see. Mainly for showing which burst rx/tx module running:

https://docs.fd.io/vpp/18.11/d7/d1d/plugins_2dpdk_2device_2format_8c_source.html

s = format (s, "%Utx burst function: %s\n",
  579                   format_white_space, indent + 2,
  580                   ptr2sname (rte_eth_devices[xd->port_id].tx_pkt_burst));
  581       s = format (s, "%Urx burst function: %s\n",
  582                   format_white_space, indent + 2,
  583                   ptr2sname (rte_eth_devices[xd->port_id].rx_pkt_burst));

https://docs.fd.io/vpp/18.11/d7/d1d/plugins_2dpdk_2device_2format_8c_source.html

488 static const char *
  489 ptr2sname (void *p)
  490 {
  491   Dl_info info = { 0 };
  492 
  493   if (dladdr (p, &info) == 0)
  494     return 0;
  495 
  496   return info.dli_sname;
  497 }

    tx burst function: ixgbe_xmit_pkts
    rx burst function: ixgbe_recv_pkts

If the PMD's rx/tx is *static* function, 'ptr2name' returns 'nil'.

  reply	other threads:[~2019-10-29  5:42 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-15  7:51 [dpdk-dev] [PATCH v4 0/4] get Rx/Tx packet " Haiyue Wang
2019-10-15  7:51 ` [dpdk-dev] [PATCH v4 1/4] ethdev: add the API for getting " Haiyue Wang
2019-10-15 10:45   ` Ferruh Yigit
2019-10-15 11:23     ` Wang, Haiyue
2019-10-15 11:13   ` Ferruh Yigit
2019-10-25  9:36   ` Thomas Monjalon
2019-10-25 10:26     ` Jerin Jacob
2019-10-25 13:59     ` Wang, Haiyue
2019-10-25 14:08     ` Ferruh Yigit
2019-10-25 15:45       ` Thomas Monjalon
2019-10-25 16:02         ` Jerin Jacob
2019-10-25 22:27           ` Thomas Monjalon
2019-10-26  4:40             ` Wang, Haiyue
2019-10-26  6:24               ` Thomas Monjalon
2019-10-26  9:23                 ` Wang, Haiyue
2019-10-26 16:23                   ` Thomas Monjalon
2019-10-29 14:27                     ` Ferruh Yigit
2019-11-03 20:35                       ` Ray Kinsella
2019-11-03 22:41                         ` Thomas Monjalon
2019-11-04  9:49                           ` Ray Kinsella
2019-11-04  9:54                             ` Thomas Monjalon
2019-11-04 10:03                               ` Ray Kinsella
2019-11-04 10:46                                 ` Wang, Haiyue
2019-11-04 11:30                                 ` Thomas Monjalon
2019-11-04 12:07                                   ` Ray Kinsella
2019-11-04 13:09                                     ` Thomas Monjalon
2019-11-04 13:48                                       ` Ray Kinsella
2019-11-04 14:17                                         ` Wang, Haiyue
2019-10-26  6:40             ` Slava Ovsiienko
2019-10-26  9:31               ` Wang, Haiyue
2019-10-26  6:58             ` Jerin Jacob
2019-10-26  9:37               ` Wang, Haiyue
2019-10-29  3:37                 ` Jerin Jacob
2019-10-29  4:44                   ` Wang, Haiyue
2019-10-29  5:19                     ` Jerin Jacob
2019-10-29  5:42                       ` Wang, Haiyue [this message]
2019-10-29  5:47                         ` Jerin Jacob
2019-10-29  5:56                           ` Wang, Haiyue
2019-10-29  6:00                           ` Wang, Haiyue
2019-10-29  8:34                             ` Jerin Jacob
2019-10-29 11:26                               ` Wang, Haiyue
2019-10-29 12:56                                 ` Jerin Jacob
2019-10-29 13:51                                   ` Wang, Haiyue
2019-10-29 14:08                                     ` Jerin Jacob
2019-10-29 15:42                                       ` Wang, Haiyue
2019-10-29 15:59                                         ` Jerin Jacob
2019-10-29 16:16                                           ` Wang, Haiyue
2019-10-29 16:59               ` Ferruh Yigit
2019-10-30  4:38                 ` Jerin Jacob
2019-10-30  4:43                   ` Wang, Haiyue
2019-10-30  8:14                 ` Wang, Haiyue
2019-10-31 10:46                   ` Jerin Jacob
2019-10-31 11:15                     ` Ray Kinsella
2019-10-31 11:16                     ` Wang, Haiyue
2019-10-31 14:58                       ` Ferruh Yigit
2019-10-31 15:07                         ` Wang, Haiyue
2019-10-31 15:29                           ` Ferruh Yigit
2019-10-31 15:54                             ` Wang, Haiyue
2019-10-31 11:09                 ` Ray Kinsella
2019-10-15  7:51 ` [dpdk-dev] [PATCH v4 2/4] net/i40e: add Rx/Tx burst mode get callbacks Haiyue Wang
2019-10-15  7:51 ` [dpdk-dev] [PATCH v4 3/4] net/ice: " Haiyue Wang
2019-10-15  7:51 ` [dpdk-dev] [PATCH v4 4/4] app/testpmd: show the Rx/Tx burst mode description Haiyue Wang
2019-10-15 12:11 ` [dpdk-dev] [PATCH v4 0/4] get Rx/Tx packet burst mode information Ferruh Yigit

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