linux-kernel - [PATCH v2] tools/cpupower: Choose base_cpu to display default cpupower details

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Date:   Wed, 23 Nov 2022 13:52:08 +0530
From:   Saket Kumar Bhaskar <skb99@...ux.vnet.ibm.com>
To:     linux-kernel@...r.kernel.org
Cc:     trenn@...e.com, shuah@...nel.org, ray.huang@....com,
        linux-pm@...r.kernel.org,
        Saket Kumar Bhaskar <skb99@...ux.vnet.ibm.com>
Subject: [PATCH v2] tools/cpupower: Choose base_cpu to display default cpupower details

The default output of cpupower info utils shows unexpected output
when CPU 0 is disabled.

Considering a case where CPU 0 is disabled, output of cpupower idle-info:

Before change:
cpupower idle-info
CPUidle driver: pseries_idle
CPUidle governor: menu
analyzing CPU 0:
 *is offline

After change:
./cpupower idle-info
CPUidle driver: pseries_idle
CPUidle governor: menu
analyzing CPU 50:

Number of idle states: 2
Available idle states: snooze CEDE
snooze:
Flags/Description: snooze
Latency: 0
Usage: 101748
Duration: 2724058
CEDE:
Flags/Description: CEDE
Latency: 12
Usage: 270004
Duration: 283019526849

If -c option is not passed, CPU 0 was chosen as the default chosen CPU to
display details. However when CPU 0 is offline, it results in showing
unexpected output. This commit chooses the base_cpu
instead of CPU 0, hence keeping the output more relevant in all cases.
The base_cpu is the number of CPU on which the calling thread is
currently executing.

Signed-off-by: Saket Kumar Bhaskar <skb99@...ux.vnet.ibm.com>
---
 tools/power/cpupower/utils/cpufreq-info.c  | 4 ++--
 tools/power/cpupower/utils/cpuidle-info.c  | 4 ++--
 tools/power/cpupower/utils/cpupower-info.c | 4 ++--
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/tools/power/cpupower/utils/cpufreq-info.c b/tools/power/cpupower/utils/cpufreq-info.c
index 0646f615fe2d..c96b77365c63 100644
--- a/tools/power/cpupower/utils/cpufreq-info.c
+++ b/tools/power/cpupower/utils/cpufreq-info.c
@@ -572,9 +572,9 @@ int cmd_freq_info(int argc, char **argv)
 
 	ret = 0;
 
-	/* Default is: show output of CPU 0 only */
+	/* Default is: show output of base_cpu only */
 	if (bitmask_isallclear(cpus_chosen))
-		bitmask_setbit(cpus_chosen, 0);
+		bitmask_setbit(cpus_chosen, base_cpu);
 
 	switch (output_param) {
 	case -1:
diff --git a/tools/power/cpupower/utils/cpuidle-info.c b/tools/power/cpupower/utils/cpuidle-info.c
index f2b202c5552a..44126a87fa7a 100644
--- a/tools/power/cpupower/utils/cpuidle-info.c
+++ b/tools/power/cpupower/utils/cpuidle-info.c
@@ -176,9 +176,9 @@ int cmd_idle_info(int argc, char **argv)
 		cpuidle_exit(EXIT_FAILURE);
 	}
 
-	/* Default is: show output of CPU 0 only */
+	/* Default is: show output of base_cpu only */
 	if (bitmask_isallclear(cpus_chosen))
-		bitmask_setbit(cpus_chosen, 0);
+		bitmask_setbit(cpus_chosen, base_cpu);
 
 	if (output_param == 0)
 		cpuidle_general_output();
diff --git a/tools/power/cpupower/utils/cpupower-info.c b/tools/power/cpupower/utils/cpupower-info.c
index 06345b543786..18fd7751f509 100644
--- a/tools/power/cpupower/utils/cpupower-info.c
+++ b/tools/power/cpupower/utils/cpupower-info.c
@@ -67,9 +67,9 @@ int cmd_info(int argc, char **argv)
 	if (!params.params)
 		params.params = 0x7;
 
-	/* Default is: show output of CPU 0 only */
+	/* Default is: show output of base_cpu only */
 	if (bitmask_isallclear(cpus_chosen))
-		bitmask_setbit(cpus_chosen, 0);
+		bitmask_setbit(cpus_chosen, base_cpu);
 
 	/* Add more per cpu options here */
 	if (!params.perf_bias)
-- 
2.31.1