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tools/power turbostat: Increase CPU_SUBSET_MAXCPUS to 8192
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On systems with >= 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 >= 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 >= 1024.

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

Signed-off-by: Justin Ernst <justin.ernst@hpe.com>
Signed-off-by: Len Brown <len.brown@intel.com>
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Justin Ernst authored and Len Brown committed Apr 6, 2025
1 parent ed625c6 commit eb18754
Showing 1 changed file with 1 addition and 1 deletion.
2 changes: 1 addition & 1 deletion tools/power/x86/turbostat/turbostat.c
Original file line number Diff line number Diff line change
Expand Up @@ -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
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