Re: [dpdk-dev] [PATCH v2 1/2] lib/eal: add amd epyc2 memcpy routine to eal

[Bruce Richardson <bruce.richardson@intel.com>]

On Thu, Oct 21, 2021 at 10:14:47PM +0200, Thomas Monjalon wrote:
> 19/10/2021 12:47, Aman Kumar:
> > This patch provides rte_memcpy* calls optimized for
> > AMD EPYC platforms. Use config/x86/x86_amd_epyc_linux_gcc
> > as cross-file with meson to build dpdk for AMD EPYC platforms.
> [...]
> > --- a/config/x86/meson.build
> > +++ b/config/x86/meson.build
> > @@ -72,3 +72,10 @@ endif
> >  dpdk_conf.set('RTE_CACHE_LINE_SIZE', 64)
> >  dpdk_conf.set('RTE_MAX_LCORE', 128)
> >  dpdk_conf.set('RTE_MAX_NUMA_NODES', 32)
> > +
> > +if meson.is_cross_build()
> > +	if meson.get_cross_property('platform') == 'amd-epyc'
> > +	    dpdk_conf.set('RTE_MAX_LCORE', 512)
> > +	    dpdk_conf.set('RTE_MEMCPY_AMDEPYC', 1)
> > +	endif
> > +endif
> 
> Thinking again about the cross file.
> Why not using the meson option "cpu_instruction_set"
> to define RTE_MACHINE as "epyc" and tune other compilation options
> without using artificial cross build?
> 
> Reminder, the default in config/meson.build is:
> if cpu_instruction_set == 'generic'
>     if host_machine.cpu_family().startswith('x86')
>         cpu_instruction_set = 'corei7'
> 
> Cc Bruce who maintains this meson code.
>
Yes, that is a good suggestion. You could detect a particular instruction
set value and set additional defines based on it.

/Bruce