cpupower: Fix checks for CPU existence

PATCH New Ben Hutchings 1 participant 1 message Apr 18, 2017 CPU power monitoring

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Ben Hutchings

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2017-04-18 02:31 UTC #0 lore raw

PATCH 1/1 cpupower: Fix checks for CPU existence

Calls to cpufreq_cpu_exists(cpu) were converted to cpupower_is_cpu_online(cpu) when libcpupower was introduced and the former function was deleted. However, cpupower_is_cpu_online() returns 1 on success whereas cpufreq_cpu_exists() returned 0 on success. It also does not distinguish physically absent and offline CPUs, and does not set errno.

cpufreq-set has already been fixed (commit c25badc9ceb6).

In cpufreq-bench, which prints an error message for offline CPUs, properly distinguish and report the zero and negative cases.

Fixes ac5a181d065d ("cpupower: Add cpuidle parts into library")

Signed-off-by Ben Hutchings <[email protected]>

---

tools/power/cpupower/bench/system.c +10 -3

@@ -58,12 +58,19 @@ long long int get_time()
 
 int set_cpufreq_governor(char *governor, unsigned int cpu)
 {
+	int rc;
 
 	dprintf("set %s as cpufreq governor\n", governor);
 
-	if (cpupower_is_cpu_online(cpu) != 0) {
-		perror("cpufreq_cpu_exists");
-		fprintf(stderr, "error: cpu %u does not exist\n", cpu);
+	rc = cpupower_is_cpu_online(cpu);
+	if (rc != 1) {
+		if (rc < 0)
+			fprintf(stderr, "cpupower_is_cpu_online: %s\n",
+				strerror(-rc));
+		else
+			fprintf(stderr,
+				"error: cpu %u is offline or does not exist\n",
+				cpu);
 		return -1;
 	}