linux-kernel - Re: [Results] [RFC PATCH v4 00/40] mm: Memory Power Management

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:	Wed, 25 Sep 2013 18:14:19 -0700
From:	Arjan van de Ven <arjan@...ux.intel.com>
To:	Andi Kleen <andi@...stfloor.org>
CC:	Andrew Morton <akpm@...ux-foundation.org>,
	"Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>,
	mgorman@...e.de, dave@...1.net, hannes@...xchg.org,
	tony.luck@...el.com, matthew.garrett@...ula.com, riel@...hat.com,
	srinivas.pandruvada@...ux.intel.com, willy@...ux.intel.com,
	kamezawa.hiroyu@...fujitsu.com, lenb@...nel.org, rjw@...k.pl,
	gargankita@...il.com, paulmck@...ux.vnet.ibm.com,
	svaidy@...ux.vnet.ibm.com, isimatu.yasuaki@...fujitsu.com,
	santosh.shilimkar@...com, kosaki.motohiro@...il.com,
	linux-pm@...r.kernel.org, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: Re: [Results] [RFC PATCH v4 00/40] mm: Memory Power Management

On 9/25/2013 4:47 PM, Andi Kleen wrote:
>> Also, the changelogs don't appear to discuss one obvious downside: the
>> latency incurred in bringing a bank out of one of the low-power states
>> and back into full operation.  Please do discuss and quantify that to
>> the best of your knowledge.
>
> On Sandy Bridge the memry wakeup overhead is really small. It's on by default
> in most setups today.

yet grouping is often defeated (in current systems) due to hw level interleaving ;-(
sometimes that's a bios setting though.

in internal experimental bioses we've been able to observe a "swing" of a few watts
(not with these patches but with some other tricks)...
I'm curious to see how these patches do for Srivatsa

--
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/