From: Nick Piggin <nickpiggin@yahoo.com.au>
To: William Lee Irwin III <wli@holomorphy.com>
Cc: Marcelo Tosatti <marcelo.tosatti@cyclades.com>,
Andrew Morton <akpm@osdl.org>,
linux-kernel@vger.kernel.org
Subject: Re: [pagevec] resize pagevec to O(lg(NR_CPUS))
Date: Sun, 12 Sep 2004 14:36:22 +1000 [thread overview]
Message-ID: <4143D246.6030101@yahoo.com.au> (raw)
In-Reply-To: <20040912052308.GE2660@holomorphy.com>
William Lee Irwin III wrote:
>
> It's unclear what you're estimating the size of. PAGEVEC_SIZE of 62
Overhead of the loaded pagevec.
[snip]
>
> mapping->tree_lock is affected as well as zone->lru_lock. The workload
> obviously has to touch the relevant locks for pagevecs to be relevant;
> however, the primary factor in the effectiveness of pagevecs is the
> lock transfer time, which is not likely to vary significantly on boxen
> such as the OSDL STP machines. You should use a workload stressing
> mapping->tree_lock via codepaths using radix_tree_gang_lookup() and
> getting runtime on OSDL's NUMA-Q or otherwise asking SGI to test its
> effects, otherwise you're dorking around with boxen with identical
> characteristics as far as batched locking is concerned.
>
Yeah I forgot about that. I guess it probably would be easier to
get contention on the tree lock.
next prev parent reply other threads:[~2004-09-12 5:28 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 [this message]
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
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