[EXT] Re: [PATCH v3 1/1] app/testpmd: control passing Rx metadata to PMD

[Thomas Monjalon]

02/12/2022 17:14, Hanumanth Reddy Pothula:
> -----Original Message-----
> > 27/10/2022 09:34, Thomas Monjalon:
> > > 17/10/2022 10:32, Andrew Rybchenko:
> > > > On 10/6/22 21:35, Hanumanth Pothula wrote:
> > > > > Presently, Rx metadata is sent to PMD by default, leading to a
> > > > > performance drop as processing for the same in rx path takes extra
> > > > > cycles.
> > > > >
> > > > > Hence, introducing command line argument, 'nic-to-pmd-rx-metadata'
> > > > > to control passing rx metadata to PMD. By default it’s disabled.
> > > > >
> > > > > Signed-off-by: Hanumanth Pothula <hpothula at marvell.com>
> > > >
> > > > Acked-by: Andrew Rybchenko <andrew.rybchenko at oktetlabs.ru>
> > > >
> > > > Applied to dpdk-next-net/main, thanks.
> > >
> > > I'm not sure this patch is really acceptable.
> > > It is disabling Rx metadata by default just for benchmarking reason
> > > because your driver is doing some processing even if metadata is not
> > required.
> > >
> > > From a user perspective, if a command requesting metadata is entered,
> > > it won't work until we enable this new option on startup.
> > > It looks terrible.
> > >
> > > Please tell me I misunderstood something.
> > 
> > While pulling, I see that the name is not compliant with others.
> > I think it should start with "enable-", use hyphens and be sorted.
> > 
> > I'll drop it from the pull for now, we can have it in -rc3.
> > 
> 
> @Thomas Monjalon I missed your comment, sorry for the delayed response.
> 
> Sending Rx metadata to PMD is added recently, which breaking our driver performance.  
> Normally any feature added to testpmd will be disabled by default, to make sure it won't affect other code(PMD). 
> Hence adding new testpmd command line argument to disable this feature by default. 

No, disabling by default doesn't mean you should enable with option.
It should be enabled if required by a command.