From: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
To: Arjan van de Ven <arjan@linux.intel.com>
Cc: Andi Kleen <andi@firstfloor.org>,
Andrew Morton <akpm@linux-foundation.org>,
mgorman@suse.de, dave@sr71.net, hannes@cmpxchg.org,
tony.luck@intel.com, matthew.garrett@nebula.com, riel@redhat.com,
srinivas.pandruvada@linux.intel.com, willy@linux.intel.com,
kamezawa.hiroyu@jp.fujitsu.com, lenb@kernel.org, rjw@sisk.pl,
gargankita@gmail.com, paulmck@linux.vnet.ibm.com,
svaidy@linux.vnet.ibm.com, isimatu.yasuaki@jp.fujitsu.com,
santosh.shilimkar@ti.com, kosaki.motohiro@gmail.com,
linux-pm@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, maxime.coquelin@stericsson.com,
loic.pallardy@stericsson.com, thomas.abraham@linaro.org,
amit.kachhap@linaro.org
Subject: Re: [Results] [RFC PATCH v4 00/40] mm: Memory Power Management
Date: Thu, 26 Sep 2013 18:46:31 +0530 [thread overview]
Message-ID: <524433AF.8010102@linux.vnet.ibm.com> (raw)
In-Reply-To: <52438AA9.3020809@linux.intel.com>
On 09/26/2013 06:45 AM, Arjan van de Ven wrote:
> 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.
>
> btw note that those kind of memory power savings are content-preserving,
> so likely a whole chunk of these patches is not actually needed on SNB
> (or anything else Intel sells or sold)
>
Umm, why not? By consolidating the allocations to fewer memory regions,
this patchset also indirectly consolidates the *references* as well. And
its the lack of memory references that really makes the hardware transition
the unreferenced banks to low-power (content-preserving) states. So from what
I understand, this patchset should provide noticeable benefits on Intel/SNB
platforms as well.
(BTW, even in the prototype powerpc hardware that I mentioned, the primary
memory power savings is expected to come from content-preserving states. So
its not like this patchset was designed only for content-losing/full-poweroff
type of scenarios).
Regards,
Srivatsa S. Bhat
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next prev parent reply other threads:[~2013-09-26 13:20 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-25 23:13 [RFC PATCH v4 00/40] mm: Memory Power Management Srivatsa S. Bhat
2013-09-25 23:13 ` [RFC PATCH v4 01/40] mm: Introduce memory regions data-structure to capture region boundaries within nodes Srivatsa S. Bhat
2013-10-23 9:54 ` Johannes Weiner
2013-10-23 14:38 ` Srivatsa S. Bhat
2013-09-25 23:14 ` [RFC PATCH v4 02/40] mm: Initialize node memory regions during boot Srivatsa S. Bhat
2013-09-25 23:14 ` [RFC PATCH v4 03/40] mm: Introduce and initialize zone memory regions Srivatsa S. Bhat
2013-09-25 23:14 ` [RFC PATCH v4 04/40] mm: Add helpers to retrieve node region and zone region for a given page Srivatsa S. Bhat
2013-09-25 23:14 ` [RFC PATCH v4 05/40] mm: Add data-structures to describe memory regions within the zones' freelists Srivatsa S. Bhat
2013-09-25 23:14 ` [RFC PATCH v4 06/40] mm: Demarcate and maintain pageblocks in region-order in " Srivatsa S. Bhat
2013-09-26 22:16 ` Dave Hansen
2013-09-27 6:34 ` Srivatsa S. Bhat
2013-10-23 10:17 ` Johannes Weiner
2013-10-23 16:09 ` Srivatsa S. Bhat
2013-09-25 23:15 ` [RFC PATCH v4 07/40] mm: Track the freepage migratetype of pages accurately Srivatsa S. Bhat
2013-09-25 23:15 ` [RFC PATCH v4 08/40] mm: Use the correct migratetype during buddy merging Srivatsa S. Bhat
2013-09-25 23:15 ` [RFC PATCH v4 09/40] mm: Add an optimized version of del_from_freelist to keep page allocation fast Srivatsa S. Bhat
2013-09-25 23:15 ` [RFC PATCH v4 10/40] bitops: Document the difference in indexing between fls() and __fls() Srivatsa S. Bhat
2013-09-25 23:16 ` [RFC PATCH v4 11/40] mm: A new optimized O(log n) sorting algo to speed up buddy-sorting Srivatsa S. Bhat
2013-09-25 23:16 ` [RFC PATCH v4 12/40] mm: Add support to accurately track per-memory-region allocation Srivatsa S. Bhat
2013-09-25 23:16 ` [RFC PATCH v4 13/40] mm: Print memory region statistics to understand the buddy allocator behavior Srivatsa S. Bhat
2013-09-25 23:17 ` [RFC PATCH v4 14/40] mm: Enable per-memory-region fragmentation stats in pagetypeinfo Srivatsa S. Bhat
2013-09-25 23:17 ` [RFC PATCH v4 15/40] mm: Add aggressive bias to prefer lower regions during page allocation Srivatsa S. Bhat
2013-09-25 23:17 ` [RFC PATCH v4 16/40] mm: Introduce a "Region Allocator" to manage entire memory regions Srivatsa S. Bhat
2013-10-23 10:10 ` Johannes Weiner
2013-10-23 16:22 ` Srivatsa S. Bhat
2013-09-25 23:17 ` [RFC PATCH v4 17/40] mm: Add a mechanism to add pages to buddy freelists in bulk Srivatsa S. Bhat
2013-09-25 23:18 ` [RFC PATCH v4 18/40] mm: Provide a mechanism to delete pages from " Srivatsa S. Bhat
2013-09-25 23:18 ` [RFC PATCH v4 19/40] mm: Provide a mechanism to release free memory to the region allocator Srivatsa S. Bhat
2013-09-25 23:18 ` [RFC PATCH v4 20/40] mm: Provide a mechanism to request free memory from " Srivatsa S. Bhat
2013-09-25 23:18 ` [RFC PATCH v4 21/40] mm: Maintain the counter for freepages in " Srivatsa S. Bhat
2013-09-25 23:18 ` [RFC PATCH v4 22/40] mm: Propagate the sorted-buddy bias for picking free regions, to " Srivatsa S. Bhat
2013-09-25 23:19 ` [RFC PATCH v4 23/40] mm: Fix vmstat to also account for freepages in the " Srivatsa S. Bhat
2013-09-25 23:19 ` [RFC PATCH v4 24/40] mm: Drop some very expensive sorted-buddy related checks under DEBUG_PAGEALLOC Srivatsa S. Bhat
2013-09-25 23:19 ` [RFC PATCH v4 25/40] mm: Connect Page Allocator(PA) to Region Allocator(RA); add PA => RA flow Srivatsa S. Bhat
2013-09-25 23:19 ` [RFC PATCH v4 26/40] mm: Connect Page Allocator(PA) to Region Allocator(RA); add PA <= " Srivatsa S. Bhat
2013-09-25 23:19 ` [RFC PATCH v4 27/40] mm: Update the freepage migratetype of pages during region allocation Srivatsa S. Bhat
2013-09-25 23:20 ` [RFC PATCH v4 28/40] mm: Provide a mechanism to check if a given page is in the region allocator Srivatsa S. Bhat
2013-09-25 23:20 ` [RFC PATCH v4 29/40] mm: Add a way to request pages of a particular region from " Srivatsa S. Bhat
2013-09-25 23:20 ` [RFC PATCH v4 30/40] mm: Modify move_freepages() to handle pages in the region allocator properly Srivatsa S. Bhat
2013-09-25 23:20 ` [RFC PATCH v4 31/40] mm: Never change migratetypes of pageblocks during freepage stealing Srivatsa S. Bhat
2013-09-25 23:20 ` [RFC PATCH v4 32/40] mm: Set pageblock migratetype when allocating regions from region allocator Srivatsa S. Bhat
2013-09-25 23:21 ` [RFC PATCH v4 33/40] mm: Use a cache between page-allocator and region-allocator Srivatsa S. Bhat
2013-09-25 23:21 ` [RFC PATCH v4 34/40] mm: Restructure the compaction part of CMA for wider use Srivatsa S. Bhat
2013-09-25 23:21 ` [RFC PATCH v4 35/40] mm: Add infrastructure to evacuate memory regions using compaction Srivatsa S. Bhat
2013-09-25 23:21 ` [RFC PATCH v4 36/40] kthread: Split out kthread-worker bits to avoid circular header-file dependency Srivatsa S. Bhat
2013-09-25 23:22 ` [RFC PATCH v4 37/40] mm: Add a kthread to perform targeted compaction for memory power management Srivatsa S. Bhat
2013-09-25 23:22 ` [RFC PATCH v4 38/40] mm: Add a mechanism to queue work to the kmempowerd kthread Srivatsa S. Bhat
2013-09-25 23:22 ` [RFC PATCH v4 39/40] mm: Add intelligence in kmempowerd to ignore regions unsuitable for evacuation Srivatsa S. Bhat
2013-09-25 23:22 ` [RFC PATCH v4 40/40] mm: Add triggers in the page-allocator to kick off region evacuation Srivatsa S. Bhat
2013-09-25 23:26 ` [Results] [RFC PATCH v4 00/40] mm: Memory Power Management Srivatsa S. Bhat
2013-09-25 23:40 ` Andrew Morton
2013-09-25 23:47 ` Andi Kleen
2013-09-26 1:14 ` Arjan van de Ven
2013-09-26 13:09 ` Srivatsa S. Bhat
2013-09-26 1:15 ` Arjan van de Ven
2013-09-26 1:21 ` Andrew Morton
2013-09-26 1:50 ` Andi Kleen
2013-09-26 2:59 ` Andrew Morton
2013-09-26 13:42 ` Srivatsa S. Bhat
2013-09-26 15:58 ` Arjan van de Ven
2013-09-26 17:00 ` Srivatsa S. Bhat
2013-09-26 18:06 ` Arjan van de Ven
2013-09-26 18:33 ` Srivatsa S. Bhat
2013-09-26 18:50 ` Luck, Tony
2013-09-26 18:56 ` Srivatsa S. Bhat
2013-09-26 13:37 ` Srivatsa S. Bhat
2013-09-26 15:23 ` Arjan van de Ven
2013-09-26 13:16 ` Srivatsa S. Bhat [this message]
2013-09-26 12:58 ` Srivatsa S. Bhat
2013-09-26 15:29 ` Arjan van de Ven
2013-09-26 17:22 ` Luck, Tony
2013-09-26 17:54 ` Srivatsa S. Bhat
2013-09-26 19:38 ` Andi Kleen
2013-11-12 8:02 ` Srivatsa S. Bhat
2013-11-12 17:34 ` Dave Hansen
2013-11-12 18:44 ` Srivatsa S. Bhat
2013-11-12 18:49 ` Srivatsa S. Bhat
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