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SubjectRe: [PATCH 6/6] cpupower tools: Fix warning and a bug with the cpu package count
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On Tuesday 07 August 2012 04:24:48 Palmer Cox wrote:
> The pkgs member of cpupower_topology is being used as the number of
> cpu packages. As the comment in get_cpu_topology notes, the package ids
> are not guaranteed to be contiguous. So, simply setting pkgs to the value
> of the highest physical_package_id doesn't actually provide a count of
> the number of cpu packages. Instead, calculate pkgs by setting it to
> the number of distinct physical_packge_id values which is pretty easy
> to do after the core_info structs are sorted. Calculating pkgs this
> way also has the nice benefit of getting rid of a sign comparison warning
> that GCC 4.6 was reporting.
> ---
> tools/power/cpupower/utils/helpers/topology.c | 18 +++++++++++++-----
> 1 file changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/tools/power/cpupower/utils/helpers/topology.c b/tools/power/cpupower/utils/helpers/topology.c
> index 4e2b583..fd3cc4d 100644
> --- a/tools/power/cpupower/utils/helpers/topology.c
> +++ b/tools/power/cpupower/utils/helpers/topology.c
> @@ -64,7 +64,7 @@ static int __compare(const void *t1, const void *t2)
> */
> int get_cpu_topology(struct cpupower_topology *cpu_top)
> {
> - int cpu, cpus = sysconf(_SC_NPROCESSORS_CONF);
> + int cpu, last_pkg, cpus = sysconf(_SC_NPROCESSORS_CONF);
>
> cpu_top->core_info = malloc(sizeof(struct cpuid_core_info) * cpus);
> if (cpu_top->core_info == NULL)
> @@ -78,20 +78,28 @@ int get_cpu_topology(struct cpupower_topology *cpu_top)
> "physical_package_id",
> &(cpu_top->core_info[cpu].pkg)) < 0)
> return -1;
> - if ((int)cpu_top->core_info[cpu].pkg != -1 &&
> - cpu_top->core_info[cpu].pkg > cpu_top->pkgs)
> - cpu_top->pkgs = cpu_top->core_info[cpu].pkg;
> if(sysfs_topology_read_file(
> cpu,
> "core_id",
> &(cpu_top->core_info[cpu].core)) < 0)
> return -1;
> }
> - cpu_top->pkgs++;
>
> qsort(cpu_top->core_info, cpus, sizeof(struct cpuid_core_info),
> __compare);
>
> + /* Count the number of distinct pkgs values. This works
> + becuase the primary sort of of the core_info structs was just
becuase ... of of ... struct instead of structs

Otherwise the first 4 patches look like rather nice and straight forward
cleanups/fixes.
Feel free to add a Reviewed-by: Thomas Renninger <trenn@suse.de>

Let me have a closer look at patch 5 and 6. I had problems getting rid of
the compiler warning, looks like you found an easy way to clean this up.
I will be back and have time for this in the beginning of next week.

On which platforms (topology) did you test this?

Thomas


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