From: Borislav Petkov <bp@suse.de>
To: Huang Rui <ray.huang@amd.com>
Cc: "Guenter Roeck" <linux@roeck-us.net>,
"Peter Zijlstra" <peterz@infradead.org>,
"Jean Delvare" <jdelvare@suse.de>,
"Andy Lutomirski" <luto@amacapital.net>,
"Andreas Herrmann" <herrmann.der.user@gmail.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@kernel.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
"Len Brown" <lenb@kernel.org>,
"John Stultz" <john.stultz@linaro.org>,
"Fr�d�ric Weisbecker" <fweisbec@gmail.com>,
lm-sensors@lm-sensors.org, linux-kernel@vger.kernel.org,
x86@kernel.org,
"Andreas Herrmann" <herrmann.der.user@googlemail.com>,
"Aravind Gopalakrishnan" <Aravind.Gopalakrishnan@amd.com>,
"Fengguang Wu" <fengguang.wu@intel.com>,
"Aaron Lu" <aaron.lu@intel.com>, "Tony Li" <tony.li@amd.com>
Subject: Re: [PATCH v2 06/10] hwmon: (fam15h_power) Add ptsc counter value for accumulated power
Date: Mon, 26 Oct 2015 05:36:45 +0100 [thread overview]
Message-ID: <20151026043645.GC9328@nazgul.tnic> (raw)
In-Reply-To: <20151026033722.GD8036@hr-amur2>
On Mon, Oct 26, 2015 at 11:37:23AM +0800, Huang Rui wrote:
> On Fri, Oct 23, 2015 at 06:59:19AM -0700, Guenter Roeck wrote:
> > On 10/19/2015 07:28 PM, Huang Rui wrote:
> > >PTSC is the performance timestamp counter value in a cpu core and the
> > >cores in one compute unit have the fixed frequency. So it picks up the
> > >performance timestamp counter value of the first core per compute unit
> > >to measure the interval for average power per compute unit.
> > >
> > >Signed-off-by: Huang Rui <ray.huang@amd.com>
> > >Cc: Borislav Petkov <bp@alien8.de>
> > >Cc: Guenter Roeck <linux@roeck-us.net>
> > >Cc: Peter Zijlstra <peterz@infradead.org>
> > >Cc: Ingo Molnar <mingo@kernel.org>
> > >---
> > > arch/x86/include/asm/msr-index.h | 1 +
> > > drivers/hwmon/fam15h_power.c | 5 +++++
> > > 2 files changed, 6 insertions(+)
...
> > >@@ -132,6 +134,9 @@ static void do_read_registers_on_cu(void *_data)
> > >
> > > WARN_ON(rdmsrl_safe(MSR_F15H_CU_PWR_ACCUMULATOR,
> > > &data->cu_acc_power[cu]));
> > >+
> > >+ WARN_ON(rdmsrl_safe(MSR_F15H_PTSC,
> > >+ &data->cpu_sw_pwr_ptsc[cu]));
> > > }
> >
> > I am not really happy with those WARN_ON, or even an error message.
> > If the error is seen, it may be persistent.
> >
> > If an error check is really needed here, it might make more sense to store
> > the read error and return it to user space if the respective sysfs attribute
> > is read.
> >
>
> I am OK with removing WARN_ON here. Boris, if you also agree with it,
The real question should be: are those MSR accesses behind a CPUID flag check
which guarantees their existence?
If so, you don't really need WARN_ONs. And the MSR accesses better be
behind a CPUID flag anyway because reading non-existent MSRs is pretty
much pure waste of energy.
--
Regards/Gruss,
Boris.
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--
next prev parent reply other threads:[~2015-10-26 4:36 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-20 2:28 [PATCH v2 00/10] hwmon: (fam15h_power) Introduce an accumulated power reporting algorithm Huang Rui
2015-10-20 2:28 ` [PATCH v2 01/10] hwmon: (fam15h_power) Refactor attributes for dynamically added Huang Rui
2015-10-23 13:42 ` Guenter Roeck
2015-10-26 1:58 ` Huang Rui
2015-10-26 2:14 ` Guenter Roeck
2015-10-26 2:25 ` Huang Rui
2015-10-20 2:28 ` [PATCH v2 02/10] hwmon: (fam15h_power) Enable power1_input on AMD Carrizo Huang Rui
2015-10-23 13:45 ` Guenter Roeck
2015-10-26 2:19 ` Huang Rui
2015-10-20 2:28 ` [PATCH v2 03/10] hwmon: (fam15h_power) Add max compute unit accumulated power Huang Rui
2015-10-20 2:28 ` [PATCH v2 04/10] x86, amd: add accessor for number of cores per compute unit Huang Rui
2015-10-20 2:28 ` [PATCH v2 05/10] hwmon: (fam15h_power) Add compute unit accumulated power Huang Rui
2015-10-20 7:24 ` kbuild test robot
2015-10-21 1:42 ` Huang Rui
2015-10-21 2:15 ` Guenter Roeck
2015-10-21 2:40 ` Huang Rui
2015-10-21 2:49 ` Guenter Roeck
2015-10-21 3:04 ` Huang Rui
2015-10-21 6:05 ` Jean Delvare
2015-10-21 6:28 ` Huang Rui
2015-10-23 13:27 ` Borislav Petkov
2015-10-23 13:37 ` Guenter Roeck
2015-10-27 2:53 ` Huang Rui
2015-10-28 0:34 ` Borislav Petkov
2015-10-28 5:06 ` Huang Rui
2015-10-20 2:28 ` [PATCH v2 06/10] hwmon: (fam15h_power) Add ptsc counter value for " Huang Rui
2015-10-23 13:59 ` Guenter Roeck
2015-10-26 3:37 ` Huang Rui
2015-10-26 4:36 ` Borislav Petkov [this message]
2015-10-20 2:28 ` [PATCH v2 07/10] hwmon: (fam15h_power) Introduce a cpu accumulated power reporting algorithm Huang Rui
2015-10-23 13:28 ` Borislav Petkov
2015-10-26 3:46 ` Huang Rui
2015-10-26 4:41 ` Borislav Petkov
2015-10-23 14:20 ` Guenter Roeck
2015-10-27 3:36 ` Huang Rui
2015-10-20 2:28 ` [PATCH v2 08/10] hwmon: (fam15h_power) Add documentation for previous TDP reporting Huang Rui
2015-10-20 2:28 ` [PATCH v2 09/10] hwmon: (fam15h_power) Add documentation for accumulated power algorithm Huang Rui
2015-10-23 10:22 ` Borislav Petkov
2015-10-20 2:28 ` [PATCH v2 10/10] MAINTAINERS: change the maintainer of fam15h_power driver Huang Rui
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