From: Ingo Molnar <mingo@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Mike Travis <travis@sgi.com>, "H. Peter Anvin" <hpa@zytor.com>,
Nathan Zimmer <nzimmer@sgi.com>,
holt@sgi.com, rob@landley.net, tglx@linutronix.de,
mingo@redhat.com, yinghai@kernel.org, gregkh@linuxfoundation.org,
x86@kernel.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [RFC] Transparent on-demand memory setup initialization embedded in the (GFP) buddy allocator
Date: Wed, 26 Jun 2013 15:37:15 +0200 [thread overview]
Message-ID: <20130626133715.GA6424@gmail.com> (raw)
In-Reply-To: <20130626062850.a7ce5806.akpm@linux-foundation.org>
* Andrew Morton <akpm@linux-foundation.org> wrote:
> On Wed, 26 Jun 2013 11:22:48 +0200 Ingo Molnar <mingo@kernel.org> wrote:
>
> > except that on 32 TB
> > systems we don't spend ~2 hours initializing 8,589,934,592 page heads.
>
> That's about a million a second which is crazy slow - even my
> prehistoric desktop is 100x faster than that.
>
> Where's all this time actually being spent?
See the earlier part of the thread - apparently it's spent initializing
the page heads - remote NUMA node misses from a single boot CPU, going
across a zillion cross-connects? I guess there's some other low hanging
fruits as well - so making this easier to profile would be nice. The
profile posted was not really usable.
Btw., NUMA locality would be another advantage of on-demand
initialization: actual users of RAM tend to allocate node-local
(especially on large clusters), so any overhead will be naturally lower.
Thanks,
Ingo
next prev parent reply other threads:[~2013-06-26 13:37 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-21 16:25 [RFC 0/2] Delay initializing of large sections of memory Nathan Zimmer
2013-06-21 16:25 ` [RFC 1/2] x86_64, mm: Delay initializing large portion " Nathan Zimmer
2013-06-25 4:14 ` Rob Landley
2013-06-21 16:25 ` [RFC 2/2] x86_64, mm: Reinsert the absent memory Nathan Zimmer
2013-06-23 9:28 ` Ingo Molnar
2013-06-23 9:32 ` Ingo Molnar
2013-06-24 17:38 ` H. Peter Anvin
2013-06-24 19:39 ` Ingo Molnar
2013-06-24 20:08 ` H. Peter Anvin
2013-06-25 7:31 ` Ingo Molnar
2013-06-24 20:36 ` Nathan Zimmer
2013-06-25 7:38 ` Ingo Molnar
2013-06-25 15:07 ` H. Peter Anvin
2013-06-25 17:19 ` Mike Travis
2013-06-25 17:22 ` Mike Travis
2013-06-25 18:43 ` H. Peter Anvin
2013-06-25 18:51 ` Mike Travis
2013-06-26 9:22 ` [RFC] Transparent on-demand memory setup initialization embedded in the (GFP) buddy allocator Ingo Molnar
2013-06-26 13:28 ` Andrew Morton
2013-06-26 13:37 ` Ingo Molnar [this message]
2013-06-26 15:02 ` Nathan Zimmer
2013-06-26 16:15 ` Mike Travis
2013-06-26 12:14 ` [RFC 2/2] x86_64, mm: Reinsert the absent memory Ingo Molnar
2013-06-26 14:49 ` Nathan Zimmer
2013-06-26 15:12 ` Dave Hansen
2013-06-26 15:20 ` Nathan Zimmer
2013-06-26 15:58 ` Ingo Molnar
2013-06-26 16:11 ` Nathan Zimmer
2013-06-26 16:07 ` Mike Travis
2013-06-21 16:51 ` [RFC 0/2] Delay initializing of large sections of memory Greg KH
2013-06-21 17:03 ` H. Peter Anvin
2013-06-21 17:18 ` Nathan Zimmer
2013-06-21 17:28 ` H. Peter Anvin
2013-06-21 20:05 ` Nathan Zimmer
2013-06-21 20:08 ` H. Peter Anvin
2013-06-21 20:33 ` Nathan Zimmer
2013-06-21 21:36 ` Mike Travis
2013-06-21 21:07 ` Mike Travis
2013-06-21 18:44 ` Yinghai Lu
2013-06-21 18:50 ` Greg KH
2013-06-21 19:10 ` Yinghai Lu
2013-06-21 19:19 ` Nathan Zimmer
2013-06-21 20:28 ` Yinghai Lu
2013-06-21 20:40 ` Nathan Zimmer
2013-06-21 21:30 ` Mike Travis
2013-06-22 0:23 ` Yinghai Lu
2013-06-25 17:35 ` Mike Travis
2013-06-25 18:17 ` H. Peter Anvin
2013-06-25 18:40 ` Mike Travis
2013-06-25 18:40 ` Yinghai Lu
2013-06-25 18:44 ` H. Peter Anvin
2013-06-25 18:58 ` Mike Travis
2013-06-25 19:03 ` Yinghai Lu
2013-06-25 19:09 ` H. Peter Anvin
2013-06-25 19:28 ` Yinghai Lu
2013-06-27 6:37 ` Yinghai Lu
2013-06-27 11:05 ` Robin Holt
2013-06-27 15:50 ` Mike Travis
2013-06-26 9:23 ` Ingo Molnar
2013-06-25 18:38 ` Yinghai Lu
2013-06-25 18:42 ` Mike Travis
2013-06-21 18:36 ` Yinghai Lu
2013-06-21 18:44 ` Greg Kroah-Hartman
2013-06-21 19:00 ` Yinghai Lu
2013-06-21 21:28 ` Mike Travis
2013-06-21 21:19 ` Mike Travis
2013-06-27 3:35 [RFC] Transparent on-demand memory setup initialization embedded in the (GFP) buddy allocator Daniel J Blueman
2013-06-28 20:37 ` Nathan Zimmer
2013-06-29 7:24 ` Ingo Molnar
2013-06-29 18:03 ` Nathan Zimmer
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