linux-kernel - Re: [PATCH 09/15] x86, amd: add accessor for number of cores per compute unit

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 1 Sep 2015 17:56:00 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	Guenter Roeck <linux@...ck-us.net>
Cc:	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...nel.org>, Huang Rui <ray.huang@....com>,
	Borislav Petkov <bp@...e.de>, Jean Delvare <jdelvare@...e.de>,
	Andy Lutomirski <luto@...capital.net>,
	Andreas Herrmann <herrmann.der.user@...il.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Len Brown <lenb@...nel.org>,
	John Stultz <john.stultz@...aro.org>,
	Frédéric Weisbecker <fweisbec@...il.com>,
	lm-sensors@...sensors.org, linux-kernel@...r.kernel.org,
	x86@...nel.org,
	Andreas Herrmann <herrmann.der.user@...glemail.com>,
	Aravind Gopalakrishnan <Aravind.Gopalakrishnan@....com>,
	Fengguang Wu <fengguang.wu@...el.com>,
	Aaron Lu <aaron.lu@...el.com>, Tony Li <tony.li@....com>
Subject: Re: [PATCH 09/15] x86, amd: add accessor for number of cores per
 compute unit

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...

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
--
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/