Re: [PATCH 2/2] tools/power turbostat: Optimize core count calculation and fix naming inconsistency

[Len Brown]

Applied, thanks!

(I simplified the commit message a bit):

    tools/power turbostat: Eliminate unnecessary data structure allocation

    Linux core_id's are a per-package namespace, not a per-node namespace.

    Rename topo.cores_per_node to topo.cores_per_pkg to reflect this.

    Eliminate topo.nodes_per_pkg from the sizing for core data structures,
    since it has no role except to unnecessarily bloat the allocation.

    Validated on multiple Intel platforms (ICX/SPR/SRF/EMR/GNR/CWF) with
    various CPU online/offline configurations and SMT enabled/disabled
    scenarios.

    No functional changes.

    [lenb: commit message]
    Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx>
    Signed-off-by: Len Brown <len.brown@xxxxxxxxx>

On Tue, Mar 10, 2026 at 2:04 AM Zhang Rui <rui.zhang@xxxxxxxxx> wrote:
>
> The current core counting logic has both naming and efficiency issues.
> The variable topo.cores_per_node is misleadingly named since it actually
> represents the maximum number of cores per package, not per node. And
> the core count calculation is suboptimal and wastes memory.
>
> Rename topo.cores_per_node to topo.cores_per_pkg and improve the system
> core count calculation algorithm to avoid memory over-allocation.
>
> Validated on multiple Intel platforms (ICX/SPR/SRF/EMR/GNR/CWF) with
> various CPU online/offline configurations and SMT enabled/disabled
> scenarios. No functional changes found.
>
> Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx>
> ---
>  tools/power/x86/turbostat/turbostat.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
> index ae827485950d..ef3059ba07cd 100644
> --- a/tools/power/x86/turbostat/turbostat.c
> +++ b/tools/power/x86/turbostat/turbostat.c
> @@ -2409,7 +2409,7 @@ struct topo_params {
>         int max_l3_id;
>         int max_node_num;
>         int nodes_per_pkg;
> -       int cores_per_node;
> +       int cores_per_pkg;
>         int threads_per_core;
>  } topo;
>
> @@ -9634,9 +9634,9 @@ void topology_probe(bool startup)
>         topo.max_core_id = max_core_id; /* within a package */
>         topo.max_package_id = max_package_id;
>
> -       topo.cores_per_node = max_core_id + 1;
> +       topo.cores_per_pkg = max_core_id + 1;
>         if (debug > 1)
> -               fprintf(outf, "max_core_id %d, sizing for %d cores per package\n", max_core_id, topo.cores_per_node);
> +               fprintf(outf, "max_core_id %d, sizing for %d cores per package\n", max_core_id, topo.cores_per_pkg);
>         if (!summary_only)
>                 BIC_PRESENT(BIC_Core);
>
> @@ -9701,7 +9701,7 @@ void allocate_counters_1(struct counters *counters)
>  void allocate_counters(struct counters *counters)
>  {
>         int i;
> -       int num_cores = topo.cores_per_node * topo.nodes_per_pkg * topo.num_packages;
> +       int num_cores = topo.cores_per_pkg * topo.num_packages;
>
>         counters->threads = calloc(topo.max_cpu_num + 1, sizeof(struct thread_data));
>         if (counters->threads == NULL)
> --
> 2.43.0
>
>


-- 
Len Brown, Intel Open Source Technology Center