linux-kernel - Re: cpuinfo shows wrong MHz value

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 for Android: free password hash cracker in your pocket

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

Message-Id: <200902161947.19374.trenn@suse.de>
Date:	Mon, 16 Feb 2009 19:47:19 +0100
From:	Thomas Renninger <trenn@...e.de>
To:	Matthew Garrett <mjg59@...f.ucam.org>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: cpuinfo shows wrong MHz value

On Monday 16 February 2009 19:19:36 Matthew Garrett wrote:
> On Mon, Feb 16, 2009 at 07:13:15PM +0100, Thomas Renninger wrote:
> > On Monday 16 February 2009 17:50:08 Matthew Garrett wrote:
> > > On Mon, Feb 16, 2009 at 02:19:50PM +0000, Thomas Renninger wrote:
> > > 
> > > > There should be a message when this driver is loaded like:
> > > > "This driver is broken. Don't use it, don't complain."
> > > 
> > > Please don't. It's perfectly valid (if dumb) for machines to
> > > depend on the CPU for passive cooling even if they don't expose any P
> > > or T states.
> > No it's not valid. If the BIOS does not export these, it could be for
> > a reason.
> 
> We have to deal with insane BIOSes on a regular basis.
In this case I will agree with BIOS developers that they have to deal
with insane OS implementations...

> > > In that case p4-clockmod is the only code that can manage it. The 
> > > removal of the user-visible cpufreq interface should be a strong
> > > enough hint that it's not intended for speed control.
> > AFAIK p4-clockmode is still not synchronized with ACPI throttling?
> 
> It ought to work fine with any systems using MSR-based throttling.

This may come from the fact that throttling via ACPI would only kick in
in emergency temperature case. Exactly then, when throttling should be
used, it won't work. I tried it once and I could easily stall the system
by throttling via ACPI and p4_clockmod.

   Thomas
--
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/