Re: [dpdk-dev] [PATCH] config/x86: add support for AMD platform

[Thomas Monjalon <thomas@monjalon.net>]

02/11/2021 19:45, David Marchand:
> On Tue, Nov 2, 2021 at 3:53 PM Aman Kumar <aman.kumar@vvdntech.in> wrote:
> >
> > -Dcpu_instruction_set=znverX meson option can be used
> > to build dpdk for AMD platforms. Supported options are
> > znver1, znver2 and znver3.
> >
> > Signed-off-by: Aman Kumar <aman.kumar@vvdntech.in>
> > ---
> >  config/x86/meson.build              | 9 +++++++++
> >  doc/guides/linux_gsg/build_dpdk.rst | 2 +-
> >  2 files changed, 10 insertions(+), 1 deletion(-)
> >
> > diff --git a/config/x86/meson.build b/config/x86/meson.build
> > index 29f3dea181..21cda6fd33 100644
> > --- a/config/x86/meson.build
> > +++ b/config/x86/meson.build
> > @@ -72,3 +72,12 @@ endif
> >  dpdk_conf.set('RTE_CACHE_LINE_SIZE', 64)
> >  dpdk_conf.set('RTE_MAX_LCORE', 128)
> >  dpdk_conf.set('RTE_MAX_NUMA_NODES', 32)
> > +
> > +# AMD platform support
> > +if get_option('cpu_instruction_set') == 'znver1'
> > +    dpdk_conf.set('RTE_MAX_LCORE', 256)
> > +elif get_option('cpu_instruction_set') == 'znver2'
> > +    dpdk_conf.set('RTE_MAX_LCORE', 512)
> > +elif get_option('cpu_instruction_set') == 'znver3'
> > +    dpdk_conf.set('RTE_MAX_LCORE', 512)
> > +endif
> 
> I already replied to a similar patch earlier in this release.
> https://inbox.dpdk.org/dev/CAJFAV8z-5amvEnr3mazkTqH-7SZX_C6EqCua6UdMXXHgrcmT6g@mail.gmail.com/
> 
> So repeating the same: do you actually _need_ more than 128 lcores in
> a single DPDK application?

Yes I forgot this previous discussion concluding that we should not increase
more than 128 threads.

The --lcores syntax and David's work on rte_thread_register should unblock
most of use cases.