Le 27/11/2019 à 13:01, Gautham R. Shenoy a écrit :
From: "Gautham R. Shenoy" <e...@linux.vnet.ibm.com>
On Pseries LPARs, to calculate utilization, we need to know the
[S]PURR ticks when the CPUs were busy or idle.
The total PURR and SPURR ticks are already exposed via the per-cpu
sysfs files /sys/devices/system/cpu/cpuX/purr and
/sys/devices/system/cpu/cpuX/spurr.
This patch adds support for exposing the idle PURR and SPURR ticks via
/sys/devices/system/cpu/cpuX/idle_purr and
/sys/devices/system/cpu/cpuX/idle_spurr.
Might be a candid question, but I see in arch/powerpc/kernel/time.c that
PURR/SPURR are already taken into account by the kernel to calculate
utilisation when CONFIG_VIRT_CPU_ACCOUNTING_NATIVE is selected.
As far as I understand, you are wanting to expose this to userland to
redo the calculation there. What is wrong with the values reported by
the kernel ?
Christophe
Signed-off-by: Gautham R. Shenoy <e...@linux.vnet.ibm.com>
---
arch/powerpc/kernel/sysfs.c | 32 ++++++++++++++++++++++++++++++++
1 file changed, 32 insertions(+)
diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c
index 80a676d..42ade55 100644
--- a/arch/powerpc/kernel/sysfs.c
+++ b/arch/powerpc/kernel/sysfs.c
@@ -1044,6 +1044,36 @@ static ssize_t show_physical_id(struct device *dev,
}
static DEVICE_ATTR(physical_id, 0444, show_physical_id, NULL);
+static ssize_t idle_purr_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct cpu *cpu = container_of(dev, struct cpu, dev);
+ unsigned int cpuid = cpu->dev.id;
+ struct lppaca *cpu_lppaca_ptr = paca_ptrs[cpuid]->lppaca_ptr;
+ u64 idle_purr_cycles = be64_to_cpu(cpu_lppaca_ptr->wait_state_cycles);
+
+ return sprintf(buf, "%llx\n", idle_purr_cycles);
+}
+static DEVICE_ATTR_RO(idle_purr);
+
+DECLARE_PER_CPU(u64, idle_spurr_cycles);
+static ssize_t idle_spurr_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct cpu *cpu = container_of(dev, struct cpu, dev);
+ unsigned int cpuid = cpu->dev.id;
+ u64 *idle_spurr_cycles_ptr = per_cpu_ptr(&idle_spurr_cycles, cpuid);
+
+ return sprintf(buf, "%llx\n", *idle_spurr_cycles_ptr);
+}
+static DEVICE_ATTR_RO(idle_spurr);
+
+static void create_idle_purr_spurr_sysfs_entry(struct device *cpudev)
+{
+ device_create_file(cpudev, &dev_attr_idle_purr);
+ device_create_file(cpudev, &dev_attr_idle_spurr);
+}
+
static int __init topology_init(void)
{
int cpu, r;
@@ -1067,6 +1097,8 @@ static int __init topology_init(void)
register_cpu(c, cpu);
device_create_file(&c->dev, &dev_attr_physical_id);
+ if (firmware_has_feature(FW_FEATURE_SPLPAR))
+ create_idle_purr_spurr_sysfs_entry(&c->dev);
}
}
r = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "powerpc/topology:online",
