From: Guenter Roeck <linux@roeck-us.net>
To: Borislav Petkov <bp@alien8.de>
Cc: "Peter Zijlstra" <peterz@infradead.org>,
"Ingo Molnar" <mingo@kernel.org>, "Huang Rui" <ray.huang@amd.com>,
"Borislav Petkov" <bp@suse.de>, "Jean Delvare" <jdelvare@suse.de>,
"Andy Lutomirski" <luto@amacapital.net>,
"Andreas Herrmann" <herrmann.der.user@gmail.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
"Len Brown" <lenb@kernel.org>,
"John Stultz" <john.stultz@linaro.org>,
"Frédéric 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: [lm-sensors] [PATCH 09/15] x86, amd: add accessor for number of cores per compute unit
Date: Tue, 01 Sep 2015 16:06:52 +0000 [thread overview]
Message-ID: <55E5CD1C.4070502@roeck-us.net> (raw)
In-Reply-To: <20150901155600.GA8497@nazgul.tnic>
On 09/01/2015 08:56 AM, Borislav Petkov wrote:
> On Mon, Aug 31, 2015 at 02:24:08PM -0700, Guenter Roeck wrote:
>> That is a matter of driver implementation. Very commonly hwmon drivers
>> implement value caching, where data from the device is only read at
>> minimum intervals, and the cached values are reported if the information
>> is polled too rapidly.
>
> I don't see how we can use cached values in that case as they'd be
> basically a lie as to how much power the CU/processor has consumed. I
> guess it would be fairer to the user to warn instead and not issue any
> values or to simply delay the read to a min timeout...
>
This is all a matter of ABI description. I personally don't see the
harm in caching values for up to <n> milliseconds and documenting that
readings may reflect power consumption from <n> milliseconds ago.
However, I don't mind any other solution either if that is considered
unacceptable, as long as that solution doesn't break the ABI.
Guenter
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WARNING: multiple messages have this Message-ID (diff)
From: Guenter Roeck <linux@roeck-us.net>
To: Borislav Petkov <bp@alien8.de>
Cc: "Peter Zijlstra" <peterz@infradead.org>,
"Ingo Molnar" <mingo@kernel.org>, "Huang Rui" <ray.huang@amd.com>,
"Borislav Petkov" <bp@suse.de>, "Jean Delvare" <jdelvare@suse.de>,
"Andy Lutomirski" <luto@amacapital.net>,
"Andreas Herrmann" <herrmann.der.user@gmail.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
"Len Brown" <lenb@kernel.org>,
"John Stultz" <john.stultz@linaro.org>,
"Frédéric 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 09/15] x86, amd: add accessor for number of cores per compute unit
Date: Tue, 01 Sep 2015 09:06:52 -0700 [thread overview]
Message-ID: <55E5CD1C.4070502@roeck-us.net> (raw)
In-Reply-To: <20150901155600.GA8497@nazgul.tnic>
On 09/01/2015 08:56 AM, Borislav Petkov wrote:
> On Mon, Aug 31, 2015 at 02:24:08PM -0700, Guenter Roeck wrote:
>> That is a matter of driver implementation. Very commonly hwmon drivers
>> implement value caching, where data from the device is only read at
>> minimum intervals, and the cached values are reported if the information
>> is polled too rapidly.
>
> I don't see how we can use cached values in that case as they'd be
> basically a lie as to how much power the CU/processor has consumed. I
> guess it would be fairer to the user to warn instead and not issue any
> values or to simply delay the read to a min timeout...
>
This is all a matter of ABI description. I personally don't see the
harm in caching values for up to <n> milliseconds and documenting that
readings may reflect power consumption from <n> milliseconds ago.
However, I don't mind any other solution either if that is considered
unacceptable, as long as that solution doesn't break the ABI.
Guenter
next prev parent reply other threads:[~2015-09-01 16:06 UTC|newest]
Thread overview: 118+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-27 8:07 [lm-sensors] [PATCH 00/15] hwmon, fam15h_power: introduce an accumulated power reporting algorithm Huang Rui
2015-08-27 8:07 ` Huang Rui
2015-08-27 8:07 ` [lm-sensors] [PATCH 01/15] hwmon, fam15h_power: add support for AMD Carrizo Huang Rui
2015-08-27 8:07 ` Huang Rui
2015-08-27 14:35 ` [lm-sensors] " Guenter Roeck
2015-08-27 14:35 ` Guenter Roeck
2015-08-27 8:07 ` [lm-sensors] [PATCH 02/15] hwmon, fam15h_power: rename fam15h_power_is_internal_node0 function Huang Rui
2015-08-27 8:07 ` Huang Rui
2015-08-27 14:35 ` [lm-sensors] " Guenter Roeck
2015-08-27 14:35 ` Guenter Roeck
2015-08-27 8:07 ` [lm-sensors] [PATCH 03/15] hwmon, fam15h_power: refactor attributes for dynamically added Huang Rui
2015-08-27 8:07 ` Huang Rui
2015-08-27 14:46 ` [lm-sensors] " Guenter Roeck
2015-08-27 14:46 ` Guenter Roeck
2015-08-28 10:05 ` [lm-sensors] " Huang Rui
2015-08-28 10:05 ` Huang Rui
2015-08-27 8:07 ` [lm-sensors] [PATCH 04/15] hwmon, fam15h_power: update running_avg_capture bit field to 28 Huang Rui
2015-08-27 8:07 ` Huang Rui
2015-08-27 14:48 ` [lm-sensors] " Guenter Roeck
2015-08-27 14:48 ` Guenter Roeck
2015-08-27 8:07 ` [lm-sensors] [PATCH 05/15] hwmon, fam15h_power: enable power1_input on AMD Carrizo Huang Rui
2015-08-27 8:07 ` Huang Rui
2015-08-27 14:50 ` [lm-sensors] " Guenter Roeck
2015-08-27 14:50 ` Guenter Roeck
2015-08-27 8:07 ` [lm-sensors] [PATCH 06/15] hwmon, fam15h_power: add documentation for new processors support Huang Rui
2015-08-27 8:07 ` Huang Rui
2015-08-27 14:51 ` [lm-sensors] " Guenter Roeck
2015-08-27 14:51 ` Guenter Roeck
2015-08-27 8:07 ` [lm-sensors] [PATCH 07/15] hwmon, fam15h_power: add ratio of Tsample to the PTSC period Huang Rui
2015-08-27 8:07 ` Huang Rui
2015-08-27 14:54 ` [lm-sensors] " Guenter Roeck
2015-08-27 14:54 ` Guenter Roeck
2015-08-27 8:07 ` [lm-sensors] [PATCH 08/15] hwmon, fam15h_power: add max compute unit accumulated power Huang Rui
2015-08-27 8:07 ` Huang Rui
2015-08-27 14:56 ` [lm-sensors] " Guenter Roeck
2015-08-27 14:56 ` Guenter Roeck
2015-08-27 8:07 ` [lm-sensors] [PATCH 09/15] x86, amd: add accessor for number of cores per compute unit Huang Rui
2015-08-27 8:07 ` Huang Rui
2015-08-27 17:27 ` [lm-sensors] " Guenter Roeck
2015-08-27 17:27 ` Guenter Roeck
2015-08-28 10:28 ` [lm-sensors] " Huang Rui
2015-08-28 10:28 ` Huang Rui
2015-08-28 6:48 ` [lm-sensors] " Borislav Petkov
2015-08-28 6:48 ` Borislav Petkov
2015-08-28 8:00 ` [lm-sensors] " Guenter Roeck
2015-08-28 8:00 ` Guenter Roeck
2015-08-28 8:04 ` [lm-sensors] " Ingo Molnar
2015-08-28 8:04 ` Ingo Molnar
2015-08-28 8:56 ` [lm-sensors] " Borislav Petkov
2015-08-28 8:56 ` Borislav Petkov
2015-08-28 10:18 ` [lm-sensors] " Huang Rui
2015-08-28 10:18 ` Huang Rui
2015-08-29 9:19 ` [lm-sensors] " Ingo Molnar
2015-08-29 9:19 ` Ingo Molnar
2015-08-30 15:53 ` [lm-sensors] " Borislav Petkov
2015-08-30 15:53 ` Borislav Petkov
2015-08-31 8:38 ` [lm-sensors] " Peter Zijlstra
2015-08-31 8:38 ` Peter Zijlstra
2015-08-31 13:26 ` [lm-sensors] " Guenter Roeck
2015-08-31 13:26 ` Guenter Roeck
2015-08-31 13:38 ` [lm-sensors] " Peter Zijlstra
2015-08-31 13:38 ` Peter Zijlstra
2015-08-31 13:53 ` [lm-sensors] " Guenter Roeck
2015-08-31 13:53 ` Guenter Roeck
2015-08-31 14:57 ` [lm-sensors] " Peter Zijlstra
2015-08-31 14:57 ` Peter Zijlstra
2015-08-31 15:11 ` [lm-sensors] " Guenter Roeck
2015-08-31 15:11 ` Guenter Roeck
2015-08-31 16:06 ` [lm-sensors] " Borislav Petkov
2015-08-31 16:06 ` Borislav Petkov
2015-08-31 16:19 ` [lm-sensors] " Guenter Roeck
2015-08-31 16:19 ` Guenter Roeck
2015-08-31 20:44 ` [lm-sensors] " Peter Zijlstra
2015-08-31 20:44 ` Peter Zijlstra
2015-08-31 21:24 ` [lm-sensors] " Guenter Roeck
2015-08-31 21:24 ` Guenter Roeck
2015-09-01 15:56 ` [lm-sensors] " Borislav Petkov
2015-09-01 15:56 ` Borislav Petkov
2015-09-01 16:06 ` Guenter Roeck [this message]
2015-09-01 16:06 ` Guenter Roeck
2015-08-27 8:07 ` [lm-sensors] [PATCH 10/15] hwmon, fam15h_power: add compute unit accumulated power Huang Rui
2015-08-27 8:07 ` Huang Rui
2015-08-28 8:03 ` [lm-sensors] " Ingo Molnar
2015-08-28 8:03 ` Ingo Molnar
2015-08-28 10:42 ` [lm-sensors] " Huang Rui
2015-08-28 10:42 ` Huang Rui
2015-08-27 8:07 ` [lm-sensors] [PATCH 11/15] hwmon, fam15h_power: add ptsc counter value for " Huang Rui
2015-08-27 8:07 ` Huang Rui
2015-08-27 8:07 ` [lm-sensors] [PATCH 12/15] hwmon, fam15h_power: introduce a cpu accumulated power reporting algorith Huang Rui
2015-08-27 8:07 ` [PATCH 12/15] hwmon, fam15h_power: introduce a cpu accumulated power reporting algorithm Huang Rui
2015-08-27 17:30 ` [lm-sensors] [PATCH 12/15] hwmon, fam15h_power: introduce a cpu accumulated power reporting algo Guenter Roeck
2015-08-27 17:30 ` [PATCH 12/15] hwmon, fam15h_power: introduce a cpu accumulated power reporting algorithm Guenter Roeck
2015-08-28 10:45 ` [lm-sensors] [PATCH 12/15] hwmon, fam15h_power: introduce a cpu accumulated power reporting algo Huang Rui
2015-08-28 10:45 ` [PATCH 12/15] hwmon, fam15h_power: introduce a cpu accumulated power reporting algorithm Huang Rui
2015-08-28 14:05 ` [lm-sensors] [PATCH 12/15] hwmon, fam15h_power: introduce a cpu accumulated power reporting algo Guenter Roeck
2015-08-28 14:05 ` [PATCH 12/15] hwmon, fam15h_power: introduce a cpu accumulated power reporting algorithm Guenter Roeck
2015-08-31 4:16 ` [lm-sensors] [PATCH 12/15] hwmon, fam15h_power: introduce a cpu accumulated power reporting algo Huang Rui
2015-08-31 4:16 ` [PATCH 12/15] hwmon, fam15h_power: introduce a cpu accumulated power reporting algorithm Huang Rui
2015-08-31 4:30 ` [lm-sensors] [PATCH 12/15] hwmon, fam15h_power: introduce a cpu accumulated power reporting algo Guenter Roeck
2015-08-31 4:30 ` [PATCH 12/15] hwmon, fam15h_power: introduce a cpu accumulated power reporting algorithm Guenter Roeck
2015-08-31 13:11 ` [lm-sensors] [PATCH 12/15] hwmon, fam15h_power: introduce a cpu accumulated power reporting algo Huang Rui
2015-08-31 13:11 ` [PATCH 12/15] hwmon, fam15h_power: introduce a cpu accumulated power reporting algorithm Huang Rui
2015-08-31 13:25 ` [lm-sensors] [PATCH 12/15] hwmon, fam15h_power: introduce a cpu accumulated power reporting algo Peter Zijlstra
2015-08-31 13:25 ` [PATCH 12/15] hwmon, fam15h_power: introduce a cpu accumulated power reporting algorithm Peter Zijlstra
2015-08-31 14:59 ` [lm-sensors] [PATCH 12/15] hwmon, fam15h_power: introduce a cpu accumulated power reporting algo Peter Zijlstra
2015-08-31 14:59 ` [PATCH 12/15] hwmon, fam15h_power: introduce a cpu accumulated power reporting algorithm Peter Zijlstra
2015-08-27 8:07 ` [lm-sensors] [PATCH 13/15] hwmon, fam15h_power: add documentation for previous TDP reporting Huang Rui
2015-08-27 8:07 ` Huang Rui
2015-08-27 8:07 ` [lm-sensors] [PATCH 14/15] hwmon, fam15h_power: add documentation for accumulated power algorithm Huang Rui
2015-08-27 8:07 ` Huang Rui
2015-08-27 8:07 ` [lm-sensors] [PATCH 15/15] MAINTAINERS: change the maintainer of fam15h_power driver Huang Rui
2015-08-27 8:07 ` Huang Rui
2015-08-29 16:33 ` [lm-sensors] [15/15] " Guenter Roeck
2015-08-29 16:33 ` Guenter Roeck
2015-08-31 1:11 ` [lm-sensors] " Huang Rui
2015-08-31 1:11 ` Huang Rui
2015-08-31 15:19 ` [lm-sensors] " Andreas Herrmann
2015-08-31 15:19 ` Andreas Herrmann
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