linux-kernel - Re: [PATCH] Option to disable AMD C1E (allows dynticks to work)

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]

Message-ID: <20071214154106.4f0b2d8c@linux360.ro>
Date:	Fri, 14 Dec 2007 15:41:06 +0200
From:	Eduard-Gabriel Munteanu <eduard.munteanu@...ux360.ro>
To:	Andi Kleen <andi@...stfloor.org>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH] Option to disable AMD C1E (allows dynticks to work)

On Fri, 14 Dec 2007 11:17:21 +0100
Andi Kleen <andi@...stfloor.org> wrote:

> >so do whatever is necessary to enable dynticks. 
> 
> dynticks' main purpose is to save power, but C1e saves more power.
> Disabling C1e for dynticks would be a fairly useless default
> trade off.

I see. Also, AMD specs say that either higher C-states are enabled, or
C1E, but not both at the same time. So if the BIOS doesn't offer an
option to disable C1E, it can't provide _CST or P_LVL* ACPI
objects for higher C-states.

Dynticks also provides lower latencies as far as I know. I think this
workaround should be merged, even if as a non-default config option.

I'll resubmit a patch if you agree.

(By the way, sorry for messing up the "Cc:" fields in the previous
message.)
--
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/