cpupower: Provide online and offline CPU information

When a user tries to modify cpuidle or cpufreq properties on offline
CPUs, the tool returns success (exit status 0) but also does not provide
any warning message regarding offline cpus that may have been specified
but left unchanged. In case of all or a few CPUs being offline, it can be
difficult to keep track of which CPUs didn't get the new frequency or idle
state set. Silent failures are difficult to keep track of when there are a
huge number of CPUs on which the action is performed.

This patch adds helper functions to find both online and offline CPUs and
print them out accordingly.

We use these helper functions in cpuidle-set and cpufreq-set to print an
additional message if the user attempts to modify offline cpus.

Reported-by: Pavithra R. Prakash <pavrampu@in.ibm.com>
Signed-off-by: Brahadambal Srinivasan <latha@linux.vnet.ibm.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

tools/power/cpupower/utils/cpufreq-set.c

@@ -315,6 +315,7 @@ int cmd_freq_set(int argc, char **argv)
 		}
 	}
 
+	get_cpustate();
 
 	/* loop over CPUs */
 	for (cpu = bitmask_first(cpus_chosen);
@@ -332,5 +333,7 @@ int cmd_freq_set(int argc, char **argv)
 		}
 	}
 
+	print_offline_cpus();
+
 	return 0;
 }

tools/power/cpupower/utils/cpuidle-set.c

@@ -95,6 +95,8 @@ int cmd_idle_set(int argc, char **argv)
 		exit(EXIT_FAILURE);
 	}
 
+	get_cpustate();
+
 	/* Default is: set all CPUs */
 	if (bitmask_isallclear(cpus_chosen))
 		bitmask_setall(cpus_chosen);
@@ -181,5 +183,7 @@ int cmd_idle_set(int argc, char **argv)
 			break;
 		}
 	}
+
+	print_offline_cpus();
 	return EXIT_SUCCESS;
 }

tools/power/cpupower/utils/cpupower.c

@@ -34,6 +34,8 @@ int run_as_root;
 int base_cpu;
 /* Affected cpus chosen by -c/--cpu param */
 struct bitmask *cpus_chosen;
+struct bitmask *online_cpus;
+struct bitmask *offline_cpus;
 
 #ifdef DEBUG
 int be_verbose;
@@ -178,6 +180,8 @@ int main(int argc, const char *argv[])
 	char pathname[32];
 
 	cpus_chosen = bitmask_alloc(sysconf(_SC_NPROCESSORS_CONF));
+	online_cpus = bitmask_alloc(sysconf(_SC_NPROCESSORS_CONF));
+	offline_cpus = bitmask_alloc(sysconf(_SC_NPROCESSORS_CONF));
 
 	argc--;
 	argv += 1;
@@ -230,6 +234,10 @@ int main(int argc, const char *argv[])
 		ret = p->main(argc, argv);
 		if (cpus_chosen)
 			bitmask_free(cpus_chosen);
+		if (online_cpus)
+			bitmask_free(online_cpus);
+		if (offline_cpus)
+			bitmask_free(offline_cpus);
 		return ret;
 	}
 	print_help();

tools/power/cpupower/utils/helpers/helpers.h

@@ -94,6 +94,8 @@ struct cpupower_cpu_info {
  */
 extern int get_cpu_info(struct cpupower_cpu_info *cpu_info);
 extern struct cpupower_cpu_info cpupower_cpu_info;
+
+
 /* cpuid and cpuinfo helpers  **************************/
 
 /* X86 ONLY ****************************************/
@@ -171,4 +173,14 @@ static inline unsigned int cpuid_ecx(unsigned int op) { return 0; };
 static inline unsigned int cpuid_edx(unsigned int op) { return 0; };
 #endif /* defined(__i386__) || defined(__x86_64__) */
 
+/*
+ * CPU State related functions
+ */
+extern struct bitmask *online_cpus;
+extern struct bitmask *offline_cpus;
+
+void get_cpustate(void);
+void print_online_cpus(void);
+void print_offline_cpus(void);
+
 #endif /* __CPUPOWERUTILS_HELPERS__ */

tools/power/cpupower/utils/helpers/misc.c

@@ -1,8 +1,12 @@
 // SPDX-License-Identifier: GPL-2.0
-#if defined(__i386__) || defined(__x86_64__)
+
+#include <stdio.h>
+#include <stdlib.h>
 
 #include "helpers/helpers.h"
 
+#if defined(__i386__) || defined(__x86_64__)
+
 #define MSR_AMD_HWCR	0xc0010015
 
 int cpufreq_has_boost_support(unsigned int cpu, int *support, int *active,
@@ -41,3 +45,63 @@ int cpufreq_has_boost_support(unsigned int cpu, int *support, int *active,
 	return 0;
 }
 #endif /* #if defined(__i386__) || defined(__x86_64__) */
+
+/* get_cpustate
+ *
+ * Gather the information of all online CPUs into bitmask struct
+ */
+void get_cpustate(void)
+{
+	unsigned int cpu = 0;
+
+	bitmask_clearall(online_cpus);
+	bitmask_clearall(offline_cpus);
+
+	for (cpu = bitmask_first(cpus_chosen);
+		cpu <= bitmask_last(cpus_chosen); cpu++) {
+
+		if (cpupower_is_cpu_online(cpu) == 1)
+			bitmask_setbit(online_cpus, cpu);
+		else
+			bitmask_setbit(offline_cpus, cpu);
+
+		continue;
+	}
+}
+
+/* print_online_cpus
+ *
+ * Print the CPU numbers of all CPUs that are online currently
+ */
+void print_online_cpus(void)
+{
+	int str_len = 0;
+	char *online_cpus_str = NULL;
+
+	str_len = online_cpus->size * 5;
+	online_cpus_str = (void *)malloc(sizeof(char) * str_len);
+
+	if (!bitmask_isallclear(online_cpus)) {
+		bitmask_displaylist(online_cpus_str, str_len, online_cpus);
+		printf(_("Following CPUs are online:\n%s\n"), online_cpus_str);
+	}
+}
+
+/* print_offline_cpus
+ *
+ * Print the CPU numbers of all CPUs that are offline currently
+ */
+void print_offline_cpus(void)
+{
+	int str_len = 0;
+	char *offline_cpus_str = NULL;
+
+	str_len = offline_cpus->size * 5;
+	offline_cpus_str = (void *)malloc(sizeof(char) * str_len);
+
+	if (!bitmask_isallclear(offline_cpus)) {
+		bitmask_displaylist(offline_cpus_str, str_len, offline_cpus);
+		printf(_("Following CPUs are offline:\n%s\n"), offline_cpus_str);
+		printf(_("cpupower set operation was not performed on them\n"));
+	}
+}