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From: Lin Feng <linfeng@cn.fujitsu.com>
To: Yinghai Lu <yinghai@kernel.org>, Russ Anderson <rja@sgi.com>
Cc: Tejun Heo <tj@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Ingo Molnar <mingo@kernel.org>,
	David Rientjes <rientjes@google.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com
Subject: Re: [patch] mm: speedup in __early_pfn_to_nid
Date: Mon, 25 Mar 2013 10:11:27 +0800	[thread overview]
Message-ID: <514FB24F.8080104@cn.fujitsu.com> (raw)
In-Reply-To: <CAE9FiQUjVRUs02-ymmtO+5+SgqTWK8Ae6jJwD08uRbgR=eLJgw@mail.gmail.com>



On 03/24/2013 04:37 AM, Yinghai Lu wrote:
> +#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
> +int __init_memblock memblock_search_pfn_nid(unsigned long pfn,
> +			 unsigned long *start_pfn, unsigned long *end_pfn)
> +{
> +	struct memblock_type *type = &memblock.memory;
> +	int mid = memblock_search(type, (phys_addr_t)pfn << PAGE_SHIFT);

I'm really eager to see how much time can we save using binary search compared to
linear search in this case :)

(quote)
> A 4 TB (single rack) UV1 system takes 512 seconds to get through
> the zone code.  This performance optimization reduces the time
> by 189 seconds, a 36% improvement.
>
> A 2 TB (single rack) UV2 system goes from 212.7 seconds to 99.8 seconds,
> a 112.9 second (53%) reduction.
(quote)

thanks,
linfeng

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  reply	other threads:[~2013-03-25  2:28 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-03-18 15:56 Russ Anderson
2013-03-19  3:56 ` David Rientjes
2013-03-20 22:32 ` Andrew Morton
2013-03-21 10:55 ` Ingo Molnar
2013-03-21 12:35   ` Michal Hocko
2013-03-21 18:03     ` Ingo Molnar
2013-03-25 21:26       ` Andrew Morton
2013-03-26  8:05         ` Ingo Molnar
2013-03-21 18:40   ` David Rientjes
2013-03-22  7:25     ` Ingo Molnar
2013-03-23 15:29       ` Russ Anderson
2013-03-23 20:37         ` Yinghai Lu
2013-03-25  2:11           ` Lin Feng [this message]
2013-03-25 21:56             ` Russ Anderson
2013-03-25 22:17               ` Yinghai Lu
2013-03-23 22:24         ` KOSAKI Motohiro
2013-03-25  0:28           ` David Rientjes
2013-03-25 21:34             ` Andrew Morton
2013-03-25 22:36               ` David Rientjes
2013-03-25 22:42                 ` Andrew Morton
2013-03-24  7:43         ` Ingo Molnar

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