Re: [PATCH] test/ring_perf: add optional cross L3 core selection

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

On Fri, Oct 17, 2025 at 04:34:04PM +0000, Sivaprasad Tummala wrote:
> Enhances test_ring_perf to optionally select two cores on
> the same socket but on different L3 caches using hwloc.
> 
> This allows performance characterization of ring library
> on processors with split L3 cache architectures, providing
> more realistic measurements of inter-core communication
> and cache effects.
> 
> The feature is conditional on hwloc being present, ensuring
> builds succeed on systems without hwloc.
> 
> Signed-off-by: Sivaprasad Tummala <sivaprasad.tummala@amd.com>
> ---
>  app/test/test_ring_perf.c | 75 +++++++++++++++++++++++++++++++++++++++
>  config/meson.build        |  8 +++++
>  2 files changed, 83 insertions(+)
> 
> diff --git a/app/test/test_ring_perf.c b/app/test/test_ring_perf.c

<snip>

> diff --git a/config/meson.build b/config/meson.build
> index b8c1f127a2..75630254f2 100644
> --- a/config/meson.build
> +++ b/config/meson.build
> @@ -313,6 +313,14 @@ else
>      add_project_arguments('-include', 'rte_config.h', language: 'c')
>  endif
>  
> +hwloc_dep = dependency('hwloc', required : false)
> +if hwloc_dep.found()
> +  add_project_arguments('-DHAVE_HWLOC=1', language : 'c')
> +  add_project_link_arguments('-lhwloc', language: 'c')
> +  dpdk_extra_ldflags += '-lhwloc'
> +  message('hwloc found — enabling L3 cache–aware topology support')
> +endif
> +

Hi,

I think this is the wrong place to put this. This will make the whole DPDK
build depend on hwloc and add it to the pkg-config file.

Instead, it's only the unit test binary that actually has the dependency,
based on this patch, so just add the dep there, and add it to the cflags
for that component only.

/Bruce