Before, checking for offlined CPUs was done dirty and
it was checked whether topology parsing returned -1 values.
But this is a valid case on a Xen (and possibly other) kernels.
Do proper online/offline checking, also take CONFIG_HOTPLUG_CPU
option into account (no /sys/devices/../cpuX/online file).
Signed-off-by: Thomas Renninger <trenn@xxxxxxx>
CC: Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx>
CC: cpufreq@xxxxxxxxxxxxxxx
---
tools/power/cpupower/utils/helpers/helpers.h | 3 +
tools/power/cpupower/utils/helpers/sysfs.c | 50 ++++++++++++++++++++
tools/power/cpupower/utils/helpers/sysfs.h | 2 +
tools/power/cpupower/utils/helpers/topology.c | 5 ++-
.../cpupower/utils/idle_monitor/cpupower-monitor.c | 10 +++-
5 files changed, 66 insertions(+), 4 deletions(-)
diff --git a/tools/power/cpupower/utils/helpers/helpers.h b/tools/power/cpupower/utils/helpers/helpers.h
index 592ee36..7a83022 100644
--- a/tools/power/cpupower/utils/helpers/helpers.h
+++ b/tools/power/cpupower/utils/helpers/helpers.h
@@ -96,6 +96,9 @@ struct cpupower_topology {
int pkg;
int core;
int cpu;
+
+ /* flags */
+ unsigned int is_online:1;
} *core_info;
};
diff --git a/tools/power/cpupower/utils/helpers/sysfs.c b/tools/power/cpupower/utils/helpers/sysfs.c
index 55e2466..c634302 100644
--- a/tools/power/cpupower/utils/helpers/sysfs.c
+++ b/tools/power/cpupower/utils/helpers/sysfs.c
@@ -56,6 +56,56 @@ static unsigned int sysfs_write_file(const char *path,
return (unsigned int) numwrite;
}
+/*
+ * Detect whether a CPU is online
+ *
+ * Returns:
+ * 1 -> if CPU is online
+ * 0 -> if CPU is offline
+ * negative errno values in error case
+ */
+int sysfs_is_cpu_online(unsigned int cpu)
+{
+ char path[SYSFS_PATH_MAX];
+ int fd;
+ ssize_t numread;
+ unsigned long long value;
+ char linebuf[MAX_LINE_LEN];
+ char *endp;
+ struct stat statbuf;
+
+ snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u", cpu);
+
+ if (stat(path, &statbuf) != 0)
+ return 0;
+
+ /*
+ * kernel without CONFIG_HOTPLUG_CPU
+ * -> cpuX directory exists, but not cpuX/online file
+ */
+ snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/online", cpu);
+ if (stat(path, &statbuf) != 0)
+ return 1;
+
+ fd = open(path, O_RDONLY);
+ if (fd == -1)
+ return -errno;
+
+ numread = read(fd, linebuf, MAX_LINE_LEN - 1);
+ if (numread < 1) {
+ close(fd);
+ return -EIO;
+ }
+ linebuf[numread] = '\0';
+ close(fd);
+
+ value = strtoull(linebuf, &endp, 0);
+ if (value > 1 || value < 0)
+ return -EINVAL;
+
+ return value;
+}
+
/* CPUidle idlestate specific /sys/devices/system/cpu/cpuX/cpuidle/ access */
/*
diff --git a/tools/power/cpupower/utils/helpers/sysfs.h b/tools/power/cpupower/utils/helpers/sysfs.h
index f9373e0..8cb797b 100644
--- a/tools/power/cpupower/utils/helpers/sysfs.h
+++ b/tools/power/cpupower/utils/helpers/sysfs.h
@@ -7,6 +7,8 @@
extern unsigned int sysfs_read_file(const char *path, char *buf, size_t buflen);
+extern int sysfs_is_cpu_online(unsigned int cpu);
+
extern unsigned long sysfs_get_idlestate_latency(unsigned int cpu,
unsigned int idlestate);
extern unsigned long sysfs_get_idlestate_usage(unsigned int cpu,
diff --git a/tools/power/cpupower/utils/helpers/topology.c b/tools/power/cpupower/utils/helpers/topology.c
index 385ee5c..4eae2c4 100644
--- a/tools/power/cpupower/utils/helpers/topology.c
+++ b/tools/power/cpupower/utils/helpers/topology.c
@@ -41,6 +41,8 @@ struct cpuid_core_info {
unsigned int pkg;
unsigned int thread;
unsigned int cpu;
+ /* flags */
+ unsigned int is_online:1;
};
static int __compare(const void *t1, const void *t2)
@@ -78,6 +80,8 @@ int get_cpu_topology(struct cpupower_topology *cpu_top)
return -ENOMEM;
cpu_top->pkgs = cpu_top->cores = 0;
for (cpu = 0; cpu < cpus; cpu++) {
+ cpu_top->core_info[cpu].cpu = cpu;
+ cpu_top->core_info[cpu].is_online = sysfs_is_cpu_online(cpu);
cpu_top->core_info[cpu].pkg =
sysfs_topology_read_file(cpu, "physical_package_id");
if ((int)cpu_top->core_info[cpu].pkg != -1 &&
@@ -85,7 +89,6 @@ int get_cpu_topology(struct cpupower_topology *cpu_top)
cpu_top->pkgs = cpu_top->core_info[cpu].pkg;
cpu_top->core_info[cpu].core =
sysfs_topology_read_file(cpu, "core_id");
- cpu_top->core_info[cpu].cpu = cpu;
}
cpu_top->pkgs++;
diff --git a/tools/power/cpupower/utils/idle_monitor/cpupower-monitor.c b/tools/power/cpupower/utils/idle_monitor/cpupower-monitor.c
index ba4bf06..dd8e1ea 100644
--- a/tools/power/cpupower/utils/idle_monitor/cpupower-monitor.c
+++ b/tools/power/cpupower/utils/idle_monitor/cpupower-monitor.c
@@ -190,9 +190,13 @@ void print_results(int topology_depth, int cpu)
}
}
}
- /* cpu offline */
- if (cpu_top.core_info[cpu].pkg == -1 ||
- cpu_top.core_info[cpu].core == -1) {
+ /*
+ * The monitor could still provide useful data, for example
+ * AMD HW counters partly sit in PCI config space.
+ * It's up to the monitor plug-in to check .is_online, this one
+ * is just for additional info.
+ */
+ if (!cpu_top.core_info[cpu].is_online) {
printf(_(" *is offline\n"));
return;
} else
--
1.7.3.4
--
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