Re: [dpdk-dev] [PATCH 1/3 v2] ethdev: add rx offload to drop error packets

From: Jerin Jacob <jerinjacobk@gmail.com>
To: Nipun Gupta <nipun.gupta@nxp.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>,
	dpdk-dev <dev@dpdk.org>,  Thomas Monjalon <thomas@monjalon.net>,
	Ferruh Yigit <ferruh.yigit@intel.com>,
	 Andrew Rybchenko <arybchenko@solarflare.com>,
	Hemant Agrawal <hemant.agrawal@nxp.com>,
	 Sachin Saxena <sachin.saxena@nxp.com>,
	Rohit Raj <rohit.raj@nxp.com>
Subject: Re: [dpdk-dev] [PATCH 1/3 v2] ethdev: add rx offload to drop error packets
Date: Tue, 6 Oct 2020 17:31:21 +0530	[thread overview]
Message-ID: <CALBAE1O4bWaqDbdnEuqP2t8Lo4ow-oQ6suKHGPpc7jVBR_eR_Q@mail.gmail.com> (raw)
In-Reply-To: <AM5PR0401MB2593D8A46BE35A269D5CB8F8E60D0@AM5PR0401MB2593.eurprd04.prod.outlook.com>

On Tue, Oct 6, 2020 at 4:07 PM Nipun Gupta <nipun.gupta@nxp.com> wrote:
>
>
>
> > -----Original Message-----
> > From: Jerin Jacob <jerinjacobk@gmail.com>
> > Sent: Monday, October 5, 2020 9:40 PM
> > To: Stephen Hemminger <stephen@networkplumber.org>
> > Cc: Nipun Gupta <nipun.gupta@nxp.com>; dpdk-dev <dev@dpdk.org>; Thomas
> > Monjalon <thomas@monjalon.net>; Ferruh Yigit <ferruh.yigit@intel.com>;
> > Andrew Rybchenko <arybchenko@solarflare.com>; Hemant Agrawal
> > <hemant.agrawal@nxp.com>; Sachin Saxena <sachin.saxena@nxp.com>; Rohit
> > Raj <rohit.raj@nxp.com>
> > Subject: Re: [dpdk-dev] [PATCH 1/3 v2] ethdev: add rx offload to drop error
> > packets
> >
> > On Mon, Oct 5, 2020 at 9:05 PM Stephen Hemminger
> > <stephen@networkplumber.org> wrote:
> > >
> > > On Mon,  5 Oct 2020 12:45:04 +0530
> > > nipun.gupta@nxp.com wrote:
> > >
> > > > From: Nipun Gupta <nipun.gupta@nxp.com>
> > > >
> > > > This change adds a RX offload capability, which once enabled,
> > > > hardware will drop the packets in case there of any error in
> > > > the packet such as L3 checksum error or L4 checksum.
> >
> > IMO, Providing additional support up to the level to choose the errors
> > to drops give more control to the application. Meaning,
> > L1 errors such as FCS error
> > L2 errors ..
> > L3 errors such checksum
> > i.e ethdev spec need to have  error level supported by PMD and the
> > application can set the layers interested to drop.
>
> Agree, but 'DEV_RX_OFFLOAD_ERR_PKT_DROP' shall also be there to drop all the
> error packets? Maybe we can rename it to DEV_RX_OFFLOAD_ALL_ERR_PKT_DROP.

IMHO,  we introduce such shortcut for a single flag for all err drop
then we can not change the scheme
without an API/ABI break.

>
> Currently we have not planned to add separate knobs for separate error in
> the driver, maybe we can define them separately, or we need have them in
> this series itself?

I think, ethdev API can have the capability on what are levels it
supported, in your
driver case, you can express the same.

>
> >
> > > >
> > > > Signed-off-by: Nipun Gupta <nipun.gupta@nxp.com>
> > > > Signed-off-by: Rohit Raj <rohit.raj@nxp.com>
> > > > ---
> > > > These patches are based over series:
> > > >
> > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatchwo
> > rk.dpdk.org%2Fpatch%2F78630%2F&amp;data=02%7C01%7Cnipun.gupta%40nx
> > p.com%7C90b516fd465c48945e7008d869492b3e%7C686ea1d3bc2b4c6fa92cd9
> > 9c5c301635%7C0%7C0%7C637375110263097933&amp;sdata=RBQswMBsfpM6
> > nyKur%2FaHvOMvNK7RU%2BRyhHt%2FXBsP1OM%3D&amp;reserved=0
> > > >
> > > > Changes in v2:
> > > >  - Add support in DPAA1 driver (patch 2/3)
> > > >  - Add support and config parameter in testpmd (patch 3/3)
> > > >
> > > >  lib/librte_ethdev/rte_ethdev.h | 1 +
> > > >  1 file changed, 1 insertion(+)
> > >
> > > Maybe this should be an rte_flow match/action which would then make it
> > > more flexible?
> >
> > I think, it is not based on any Patten matching. So IMO, it should be best if it
> > is part of RX offload.
> >
> > >
> > > There is not much of a performance gain for this in real life and
> > > if only one driver supports it then I am not convinced this is needed.
> >
> > Marvell HW has this feature.