[dpdk-stable] [dpdk-dev] [PATCH] config: enable packet prefetching with Meson

[David Marchand]

On Sat, Nov 14, 2020 at 10:00 AM Thomas Monjalon <thomas at monjalon.net> wrote:
>
> 14/11/2020 09:51, Thomas Monjalon:
> > 13/11/2020 16:05, Bruce Richardson:
> > > On Fri, Nov 13, 2020 at 03:52:12PM +0100, Maxime Coquelin wrote:
> > > > With Make build system, RTE_PMD_PACKET_PREFETCH was enabled
> > > > by default. It got lost when transitioning to Meson build
> > > > system.
> > > >
> > > > In order to avoid performance changes, this patch enables
> > > > packet prefetching in rte_config.h.
> > > >
> > > > Reported-by: Marvin Liu <yong.liu at intel.com>
> > > > Suggested-by: David Marchand <david.marchand at redhat.com>
> > > > Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
> [...]
> >
> > Applied with backport info, thanks.
>
> Note that it is added back for "compatibility",
> but I am still in favour of dropping this config option,
> replaced by arch decision if any:
> http://inbox.dpdk.org/dev/3677226.MZCibFMyqQ@thomas/
>
> The decision of such optimization should be done in DPDK project,
> not in the hand of the packager.

I am for dropping this too.
And for cleaning more prefetch-related stuff, like:

#if 1
#define RTE_PMD_USE_PREFETCH
#endif

#ifdef RTE_PMD_USE_PREFETCH
#define rte_em_prefetch(p)     rte_prefetch0(p)
#else
#define rte_em_prefetch(p)     do {} while(0)
#endif

This has been copied into other drivers.
The igc driver forgot(?) to force #define this macro, so it just
copied unused code.


-- 
David Marchand