From: Gautham R Shenoy <ego@linux.vnet.ibm.com>
To: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>,
"Gautham R. Shenoy" <ego@linux.vnet.ibm.com>,
Tyrel Datwyler <tyreld@linux.ibm.com>,
linux-kernel@vger.kernel.org,
"Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>,
Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 2/3] powerpc/sysfs: Show idle_purr and idle_spurr for every CPU
Date: Wed, 4 Dec 2019 18:07:28 +0530 [thread overview]
Message-ID: <20191204123728.GD5197@in.ibm.com> (raw)
In-Reply-To: <9b8f82b0-86dd-d524-aae6-34f8c33bd2c2@linux.vnet.ibm.com>
Hi Kamalesh,
On Tue, Dec 03, 2019 at 07:07:53PM +0530, Kamalesh Babulal wrote:
> On 11/27/19 5:31 PM, Gautham R. Shenoy wrote:
> > 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.
>
> The patch looks good to me, with a minor file mode nit pick mentioned below.
>
> >
> > 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);
>
> 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.
Thanks for catching this. I missed checking the permissions of purr
and spurr. Will send another version.
>
> --
> Kamalesh
next prev parent reply other threads:[~2019-12-04 12:49 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 [this message]
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
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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