cpupower tools: Fix warning and a bug with the cpu package count

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.

Signed-off-by: Palmer Cox <p@lmercox.com>
Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 13 insertions, 5 deletions

diff --git a/tools/power/cpupower/utils/helpers/topology.c b/tools/power/cpupower/utils/helpers/topology.c
index 4e2b583ea17b..c13120af519b 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
+           because the primary sort of the core_info struct was just
+           done by pkg value. */
+        last_pkg = cpu_top->core_info[0].pkg;
+        for(cpu = 1; cpu < cpus; cpu++) {
+                if(cpu_top->core_info[cpu].pkg != last_pkg) {
+                        last_pkg = cpu_top->core_info[cpu].pkg;
+                        cpu_top->pkgs++;
+                }
+        }
+        cpu_top->pkgs++;
+
         /* Intel's cores count is not consecutively numbered, there may
          * be a core_id of 3, but none of 2. Assume there always is 0
          * Get amount of cores by counting duplicates in a package