From: Bruce Richardson <bruce.richardson@intel.com>
Sent: Friday, October 17, 2025 10:10 PM
To: Tummala, Sivaprasad <Sivaprasad.Tummala@amd.com>
Cc: david.hunt@intel.com <david.hunt@intel.com>; honnappa.nagarahalli@arm.com <honnappa.nagarahalli@arm.com>; anatoly.burakov@intel.com <anatoly.burakov@intel.com>; jerinj@marvell.com <jerinj@marvell.com>; radu.nicolau@intel.com <radu.nicolau@intel.com>; gakhil@marvell.com <gakhil@marvell.com>; cristian.dumitrescu@intel.com <cristian.dumitrescu@intel.com>; Yigit, Ferruh <Ferruh.Yigit@amd.com>; konstantin.ananyev@huawei.com <konstantin.ananyev@huawei.com>; dev@dpdk.org <dev@dpdk.org>
Subject: Re: [PATCH] test/ring_perf: add optional cross L3 core selection

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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