From: Christophe Leroy <christophe.leroy@c-s.fr>
To: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>,
Nathan Lynch <nathanl@linux.ibm.com>,
Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>,
"Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>,
Tyrel Datwyler <tyreld@linux.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/3] powerpc/sysfs: Show idle_purr and idle_spurr for every CPU
Date: Wed, 5 Feb 2020 08:08:46 +0100 [thread overview]
Message-ID: <b26cedb0-8b12-71b6-63d2-990186cd49e5@c-s.fr> (raw)
In-Reply-To: <1574856072-30972-3-git-send-email-ego@linux.vnet.ibm.com>
Le 27/11/2019 à 13:01, Gautham R. Shenoy a écrit :
> From: "Gautham R. Shenoy" <ego@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 <ego@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",
>
next prev parent reply other threads:[~2020-02-05 7:08 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-27 12:01 [PATCH 0/3] pseries: Track and expose idle PURR and SPURR ticks Gautham R. Shenoy
2019-11-27 12:01 ` [PATCH 1/3] powerpc/pseries: Account for SPURR ticks on idle CPUs Gautham R. Shenoy
2019-12-03 13:39 ` Kamalesh Babulal
2019-12-04 22:24 ` Nathan Lynch
2020-02-03 4:45 ` Gautham R Shenoy
2019-11-27 12:01 ` [PATCH 2/3] powerpc/sysfs: Show idle_purr and idle_spurr for every CPU Gautham R. Shenoy
2019-12-03 13:37 ` Kamalesh Babulal
2019-12-04 12:37 ` Gautham R Shenoy
2019-12-03 21:02 ` kbuild test robot
2019-12-04 22:24 ` Nathan Lynch
2020-02-03 4:47 ` Gautham R Shenoy
2019-12-05 16:53 ` Naveen N. Rao
2020-02-03 4:50 ` Gautham R Shenoy
2020-02-04 7:52 ` Naveen N. Rao
2020-02-05 4:19 ` Gautham R Shenoy
2020-02-05 6:58 ` Naveen N. Rao
2020-02-05 7:08 ` Christophe Leroy [this message]
2020-02-05 8:07 ` Naveen N. Rao
2019-11-27 12:01 ` [PATCH 3/3] Documentation: Document sysfs interfaces purr, spurr, idle_purr, idle_spurr Gautham R. Shenoy
2019-12-04 22:25 ` Nathan Lynch
2019-12-04 22:24 ` [PATCH 0/3] pseries: Track and expose idle PURR and SPURR ticks Nathan Lynch
2019-12-05 15:03 ` Kamalesh Babulal
2019-12-05 16:16 ` Nathan Lynch
2019-12-05 17:25 ` Naveen N. Rao
2019-12-06 9:14 ` Naveen N. Rao
2020-02-04 9:12 ` Kamalesh Babulal
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