Re: [dpdk-dev] [dpdk-stable] [PATCH] net/mlx5: fix ConnectX-4LX Tx burst routines set

[Slava Ovsiienko <viacheslavo@mellanox.com>]

> -----Original Message-----
> From: Ferruh Yigit <ferruh.yigit@intel.com>
> Sent: Thursday, January 9, 2020 12:50
> To: Slava Ovsiienko <viacheslavo@mellanox.com>; dev@dpdk.org
> Cc: Matan Azrad <matan@mellanox.com>; Raslan Darawsheh
> <rasland@mellanox.com>; Ori Kam <orika@mellanox.com>; stable@dpdk.org;
> Thomas Monjalon <thomas@monjalon.net>
> Subject: Re: [dpdk-stable] [PATCH] net/mlx5: fix ConnectX-4LX Tx burst
> routines set
> 
> On 1/9/2020 9:03 AM, Slava Ovsiienko wrote:
> >> -----Original Message-----
> >> From: Ferruh Yigit <ferruh.yigit@intel.com>
> >> Sent: Wednesday, January 8, 2020 17:55
> >> To: Slava Ovsiienko <viacheslavo@mellanox.com>; dev@dpdk.org
> >> Cc: Matan Azrad <matan@mellanox.com>; Raslan Darawsheh
> >> <rasland@mellanox.com>; Ori Kam <orika@mellanox.com>;
> >> stable@dpdk.org; Thomas Monjalon <thomas@monjalon.net>
> >> Subject: Re: [dpdk-stable] [PATCH] net/mlx5: fix ConnectX-4LX Tx
> >> burst routines set
> >>
> >> On 1/8/2020 3:50 PM, Slava Ovsiienko wrote:
> >>> Hi, Ferruh
> >>>
> >>>> -----Original Message-----
> >>>> From: Ferruh Yigit <ferruh.yigit@intel.com>
> >>>> Sent: Wednesday, January 8, 2020 16:55
> >>>> To: Slava Ovsiienko <viacheslavo@mellanox.com>; dev@dpdk.org
> >>>> Cc: Matan Azrad <matan@mellanox.com>; Raslan Darawsheh
> >>>> <rasland@mellanox.com>; Ori Kam <orika@mellanox.com>;
> >>>> stable@dpdk.org; Thomas Monjalon <thomas@monjalon.net>
> >>>> Subject: Re: [dpdk-stable] [PATCH] net/mlx5: fix ConnectX-4LX Tx
> >>>> burst routines set
> >>>>
> >>>> On 1/8/2020 2:53 PM, Ferruh Yigit wrote:
> >>>>> On 12/20/2019 10:48 AM, Viacheslav Ovsiienko wrote:
> >>>>>> The tx_burst routine supporting multi-segment packets with legacy
> >>>>>> MPW and without inline was missed, and there was no valid
> >>>>>> selection for these options, patch adds the missing routine.
> >>>>>>
> >>>>>> Fixes: 82e75f8323bf ("net/mlx5: fix legacy multi-packet Tx
> >>>>>> descriptors")
> >>>>>> Cc: stable@dpdk.org
> >>>>>>
> >>>>>> Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
> >>
> >> <...>
> >>
> >>>>>> @@ -5297,6 +5305,7 @@ enum mlx5_txcmp_code {
> >>>>>>  		DRV_LOG(DEBUG, "port %u has no selected Tx
> function"
> >>>>>>  			       " for requested offloads %04X",
> >>>>>>  				dev->data->port_id, olx);
> >>>>>> +		assert(false);
> >>
> >> <...>
> >>
> >>>
> >>>>
> >>>>>
> >>>>> I think we should avoid PMDs calling the assert unconditionally,
> >>>>> specially in a code that debug level log is printed.
> >>>>>
> >>>>>>  		return NULL;
> >>>>>>  	}
> >>>>>>  	DRV_LOG(DEBUG, "port %u has selected Tx function"
> >>>
> >>> Yes, I agree. We just do not have the check for the result returned
> >>> by mlx5_select_tx_function(). I think we should check against NULL
> >>> and report an error.  "assert" is a temporary solution till this
> >>> upgrade (in debug mode we have a lot of messages and break on assert
> >>> helps to locate the problem quickly, reporting error will do the same).
> >>>
> >>
> >> Can it be possible to drop the patch from mlx tree and prepare a new
> >> version without 'assert'?
> > The selection routine error handling is rather generic and is not merely
> related to ConnectX-4LX.
> > I propose to prepare the dedicated patch, what do you  think?
> >
> 
> My concern is with the assert, the error handling can be another patch, but
> can we have this change without an assert? 

Yes, please: http://patches.dpdk.org/patch/64340/

With best regards, Slava

PS. Removing this assert urges me to add error handling ASAP 😊