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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.

  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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