tools/power turbostat: Increase CPU_SUBSET_MAXCPUS to 8192

justinrernst · lenb · commit eb187540d13a · 2025-04-06T12:14:14.000-04:00
On systems with &gt;= 1024 cpus (in my case 1152), turbostat fails with the error output:
	"turbostat: /sys/fs/cgroup/cpuset.cpus.effective: cpu str malformat 0-1151"

A similar error appears with the use of turbostat --cpu when the inputted cpu
range contains a cpu number &gt;= 1024:
	# turbostat -c 1100-1151
	"--cpu 1100-1151" malformed
	...

Both errors are caused by parse_cpu_str() reaching its limit of CPU_SUBSET_MAXCPUS.

It's a good idea to limit the maximum cpu number being parsed, but 1024 is too low.
For a small increase in compute and allocated memory, increasing CPU_SUBSET_MAXCPUS
brings support for parsing cpu numbers &gt;= 1024.

Increase CPU_SUBSET_MAXCPUS to 8192, a common setting for CONFIG_NR_CPUS on x86_64.

Signed-off-by: Justin Ernst &lt;justin.ernst@hpe.com&gt;
Signed-off-by: Len Brown &lt;len.brown@intel.com&gt;
diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
@@ -1121,7 +1121,7 @@ void probe_platform_features(unsigned int family, unsigned int model)
 int backwards_count;
 char *progname;
 
-#define CPU_SUBSET_MAXCPUS	1024	/* need to use before probe... */
+#define CPU_SUBSET_MAXCPUS	8192	/* need to use before probe... */
 cpu_set_t *cpu_present_set, *cpu_possible_set, *cpu_effective_set, *cpu_allowed_set, *cpu_affinity_set, *cpu_subset;
 size_t cpu_present_setsize, cpu_possible_setsize, cpu_effective_setsize, cpu_allowed_setsize, cpu_affinity_setsize, cpu_subset_size;
 #define MAX_ADDED_THREAD_COUNTERS 24
