From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Marcelo Tosatti <marcelo.tosatti@cyclades.com>
Cc: William Lee Irwin III <wli@holomorphy.com>,
Andrew Morton <akpm@osdl.org>,
linux-kernel@vger.kernel.org
Subject: Re: [pagevec] resize pagevec to O(lg(NR_CPUS))
Date: Tue, 14 Sep 2004 11:59:43 +1000 [thread overview]
Message-ID: <4146508F.9080700@yahoo.com.au> (raw)
In-Reply-To: <20040913222127.GA23588@logos.cnet>
Marcelo Tosatti wrote:
>>Sure. And when you fill it with pages, they'll use up 32KB of dcache
>>by using a single 64B line per page. Now that you've blown the cache,
>>when you go to move those pages to another list, you'll have to pull
>>them out of L2 again one at a time.
>>
>>OK, so a 511 item pagevec is pretty unlikely. How about a 64 item one
>>with 128 byte cachelines, and you're touching two cachelines per
>>page operation? That's 16K.
>
>
> Nick,
>
> Note that you dont read/write data to the actual pages most of the
> times pagevec's are used. The great majority is just page management code.
> So we dont really blow the caches like you said.
>
You're often pulling them off lists though which is what will do it.
Not the actual page, but the struct page.
> I agree we need more tests :)
>
Yep.
prev parent reply other threads:[~2004-09-14 1:59 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-09-09 16:39 [PATCH] cacheline align pagevec structure Marcelo Tosatti
2004-09-09 22:49 ` Andrew Morton
2004-09-09 21:41 ` Marcelo Tosatti
2004-09-09 23:20 ` Andrew Morton
2004-09-09 22:52 ` Andrew Morton
2004-09-09 23:09 ` William Lee Irwin III
2004-09-09 22:12 ` Marcelo Tosatti
2004-09-09 23:59 ` William Lee Irwin III
2004-09-09 23:22 ` Andrew Morton
2004-09-10 0:07 ` [pagevec] resize pagevec to O(lg(NR_CPUS)) William Lee Irwin III
2004-09-10 4:56 ` Nick Piggin
2004-09-10 4:59 ` Nick Piggin
2004-09-10 17:49 ` Marcelo Tosatti
2004-09-12 0:29 ` Nick Piggin
2004-09-12 5:23 ` William Lee Irwin III
2004-09-12 4:36 ` Nick Piggin
2004-09-12 4:56 ` William Lee Irwin III
2004-09-12 4:28 ` Nick Piggin
2004-09-12 6:27 ` William Lee Irwin III
2004-09-12 6:03 ` Nick Piggin
2004-09-12 7:19 ` William Lee Irwin III
2004-09-12 7:42 ` Andrew Morton
2004-09-14 2:18 ` William Lee Irwin III
2004-09-14 2:57 ` Andrew Morton
2004-09-14 3:12 ` William Lee Irwin III
2004-09-12 8:57 ` William Lee Irwin III
2004-09-13 22:21 ` Marcelo Tosatti
2004-09-14 1:59 ` Nick Piggin [this message]
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