linux-kernel - Re: [PATCH 1/2] x86, mce, therm_throt: Optimize logging of thermal throttle messages

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, 15 Oct 2019 10:48:33 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
Cc:     tony.luck@...el.com, bp@...en8.de, tglx@...utronix.de,
        mingo@...hat.com, hpa@...or.com, bberg@...hat.com, x86@...nel.org,
        linux-edac@...r.kernel.org, linux-kernel@...r.kernel.org,
        hdegoede@...hat.com, ckellner@...hat.com
Subject: Re: [PATCH 1/2] x86, mce, therm_throt: Optimize logging of thermal
 throttle messages

On Mon, Oct 14, 2019 at 02:21:00PM -0700, Srinivas Pandruvada wrote:
> Some modern systems have very tight thermal tolerances. Because of this
> they may cross thermal thresholds when running normal workloads (even
> during boot). The CPU hardware will react by limiting power/frequency
> and using duty cycles to bring the temperature back into normal range.
> 
> Thus users may see a "critical" message about the "temperature above
> threshold" which is soon followed by "temperature/speed normal". These
> messages are rate limited, but still may repeat every few minutes.
> 
> The solution here is to set a timeout when the temperature first exceeds
> the threshold.

Why can we even reach critical thresholds when the fans are working? I
always thought it was BAD to ever reach the critical temps and have the
hardware throttle.