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From: Nick Piggin <nickpiggin@yahoo.com.au>
To: James Bottomley <James.Bottomley@SteelEye.com>
Cc: Sonny Rao <sonnyrao@us.ibm.com>, Andrew Morton <akpm@osdl.org>,
	Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] make radix tree gang lookup faster by using a bitmap search
Date: Tue, 30 Aug 2005 12:53:18 +1000	[thread overview]
Message-ID: <4313CA1E.3000605@yahoo.com.au> (raw)
In-Reply-To: <1125369981.5089.106.camel@mulgrave>

James Bottomley wrote:

>On Tue, 2005-08-30 at 10:56 +1000, Nick Piggin wrote:
>
>
>>Gang lookup is mainly used on IO paths but also on truncate,
>>which is a reasonably fast path on some workloads (James,
>>this is my suggestion for what you should test - truncate).
>>
>
>Actually, I don't think I can test this.  In order to show a difference
>between index 5 and index 6 on 32 bit, I'd have to deal with files > 4GB
>in size.  My 32 bit machines are the voyagers and only have 4GB discs.
>
>The machine with all the huge discs, is, naturally, ia64.
>
>

Sorry, I meant for testing your gang lookup speedups.

For testing regular lookups, yeah that's more difficult. For a
microbenchmark you can use sparse files, which can be a good
trick for testing pagecache performance without the IO.

Nick


Send instant messages to your online friends http://au.messenger.yahoo.com 

  reply	other threads:[~2005-08-30  3:16 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-08-27 16:26 [PATCH] make radix tree gang lookup faster by using a bitmap search James Bottomley
2005-08-27 17:53 ` Andrew Morton
2005-08-28 19:43   ` James Bottomley
2005-08-28 20:00     ` Linus Torvalds
2005-08-28 20:39       ` Andrew Morton
2005-08-29  0:45   ` James Bottomley
2005-08-29  0:52     ` Andrew Morton
2005-08-29  1:19       ` James Bottomley
2005-08-29  1:35         ` Andrew Morton
2005-08-29  3:26           ` James Bottomley
2005-08-29  3:37             ` Nick Piggin
2005-08-29  3:54               ` Trond Myklebust
2005-08-29 13:16                 ` Luben Tuikov
2005-08-29 15:01               ` James Bottomley
     [not found]               ` <20050829164144.GC9508@localhost.localdomain>
2005-08-30  0:56                 ` Nick Piggin
2005-08-30  1:54                   ` Andrew Morton
2005-08-30  2:46                   ` James Bottomley
2005-08-30  2:53                     ` Nick Piggin [this message]
     [not found]                       ` <20050830052405.GB20843@localhost.localdomain>
2005-08-30 13:06                         ` Nick Piggin

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