Re: [PATCH 2/3] powerpc/sysfs: Show idle_purr and idle_spurr for every CPU
From: Kamalesh Babulal <hidden>
Date: 2019-12-03 13:38:07
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On 11/27/19 5:31 PM, Gautham R. Shenoy wrote:
From: "Gautham R. Shenoy" <redacted> 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.
The patch looks good to me, with a minor file mode nit pick mentioned below.
quoted hunk ↗ jump to hunk
Signed-off-by: Gautham R. Shenoy <redacted> --- 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);
per cpu purr/spurr sysfs file is created with file mode 0400. Using DEVICE_ATTR_RO for their idle_* variants will create sysfs files with 0444 as their file mode, you should probably use DEVICE_ATTR() with file mode 0400 to have consist permission for both variants. -- Kamalesh