Re: [dpdk-dev] [PATCH 09/22] net/bnxt: use dedicated cpr for async events

[Lance Richardson <lance.richardson@broadcom.com>]

On Mon, Jul 22, 2019 at 11:06 AM Thomas Monjalon <thomas@monjalon.net> wrote:
>
> 22/07/2019 16:57, Ferruh Yigit:
> > On 7/18/2019 4:36 AM, Ajit Khaparde wrote:
> > > From: Lance Richardson <lance.richardson@broadcom.com>
> > > --- a/config/common_base
> > > +++ b/config/common_base
> > > @@ -212,6 +212,7 @@ CONFIG_RTE_LIBRTE_BNX2X_DEBUG_PERIODIC=n
> > >  # Compile burst-oriented Broadcom BNXT PMD driver
> > >  #
> > >  CONFIG_RTE_LIBRTE_BNXT_PMD=y
> > > +CONFIG_RTE_LIBRTE_BNXT_SHARED_ASYNC_RING=n
> >
> > Normally we don't want to introduce new config time options as much as possible.
> >
> > This is what happens when patches slip in the last minute, please Ajit try to
> > send patches before proposal next time.
> >
> > And back to the config option, is it something have to be a compile time flag
> > (if so why?), can it be replaced by a devarg?
>
> I confirm it is nack.
> I don't see any reason not to replace it with a runtime devargs.
>
>

This build-time configuration option was introduced because the
"shared async completion
ring" configuration is needed for one specific platform,
arm64-stingray-linux-gcc. This
configuration has a number of drawbacks and should be avoided
otherwise. Making it
a run-time option will add complexity and introduce the possibility
that existing stingray
users will not know that they need to specify this option as of 19.08,
so it would be good
if some other way could be found to handle this.

Other than perhaps using RTE_ARCH_ARM64 to select the shared completion ring
configuration (which would obviously affect all ARM64 users), are
there any other options
that might be acceptable?

It's maybe worthwhile to note that the last several DPDK releases use
the "shared completion
ring" configuration.

Thanks and regards,

   Lance