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From:   Brahadambal Srinivasan <latha@linux.vnet.ibm.com>
To:     shuah@kernel.org, trenn@suse.com
Cc:     linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
        latha@linux.vnet.ibm.com,
        "Pavithra R . Prakash" <pavrampu@in.ibm.com>
Subject: [PATCH v3] cpupower: Provide online and offline CPU information
Date:   Fri, 16 Oct 2020 14:29:29 +0530
Message-Id: <20201016085929.86252-1-latha@linux.vnet.ibm.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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.

In v1 of this patch, I had sent tried to address this with repetitive code
in both cpufreq-set and cpuidle-set. V2 incorporated the review comments
and added helper functions to find both online and offline CPUs and print
them out accordingly. Correcting compile issues in v3.

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>
---
 tools/power/cpupower/utils/cpufreq-set.c     |  3 +
 tools/power/cpupower/utils/cpuidle-set.c     |  4 ++
 tools/power/cpupower/utils/cpupower.c        |  8 +++
 tools/power/cpupower/utils/helpers/helpers.h | 12 ++++
 tools/power/cpupower/utils/helpers/misc.c    | 66 +++++++++++++++++++-
 5 files changed, 92 insertions(+), 1 deletion(-)

diff --git a/tools/power/cpupower/utils/cpufreq-set.c b/tools/power/cpupower/utils/cpufreq-set.c
index 6ed82fba5aaa..f25cdfa05c5f 100644
--- a/tools/power/cpupower/utils/cpufreq-set.c
+++ b/tools/power/cpupower/utils/cpufreq-set.c
@@ -311,6 +311,7 @@ int cmd_freq_set(int argc, char **argv)
 		}
 	}
 
+	get_cpustate();
 
 	/* loop over CPUs */
 	for (cpu = bitmask_first(cpus_chosen);
@@ -328,5 +329,7 @@ int cmd_freq_set(int argc, char **argv)
 		}
 	}
 
+	print_offline_cpus();
+
 	return 0;
 }
diff --git a/tools/power/cpupower/utils/cpuidle-set.c b/tools/power/cpupower/utils/cpuidle-set.c
index 569f268f4c7f..46158928f9ad 100644
--- a/tools/power/cpupower/utils/cpuidle-set.c
+++ b/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;
 }
diff --git a/tools/power/cpupower/utils/cpupower.c b/tools/power/cpupower/utils/cpupower.c
index 8e3d08042825..8ac3304a9957 100644
--- a/tools/power/cpupower/utils/cpupower.c
+++ b/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();
diff --git a/tools/power/cpupower/utils/helpers/helpers.h b/tools/power/cpupower/utils/helpers/helpers.h
index c258eeccd05f..d5799aa71e1f 100644
--- a/tools/power/cpupower/utils/helpers/helpers.h
+++ b/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__ */
diff --git a/tools/power/cpupower/utils/helpers/misc.c b/tools/power/cpupower/utils/helpers/misc.c
index f406adc40bad..2ead98169cf5 100644
--- a/tools/power/cpupower/utils/helpers/misc.c
+++ b/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"));
+	}
+}
-- 
2.27.0