From: Matthieu CASTET <matthieu.castet@parrot.com>
To: "Jörn Engel" <joern@logfs.org>
Cc: David Woodhouse <dwmw2@infradead.org>,
Josh Boyer <jwboyer@gmail.com>,
linux-mtd@lists.infradead.org
Subject: Re: Jffs2 and big file = very slow jffs2_garbage_collect_pass
Date: Mon, 21 Jan 2008 16:57:59 +0100 [thread overview]
Message-ID: <4794C107.7070600@parrot.com> (raw)
In-Reply-To: <20080118181744.GA15039@lazybastard.org>
Hi,
Jörn Engel wrote:
> On Fri, 18 January 2008 11:55:31 -0600, Josh Boyer wrote:
>> That seems consistent with JFFS2 doing the CRC checks and constructing
>> the in-memory representation of your large file. I suspect the older
>> list-based in-memory implementation would have taken even longer, but
>> there could be something amiss with the rb-tree stuff perhaps.
>
> There is something conceptually amiss with rb-trees. Each node
> effectively occupies its own cacheline. With those 40k+ nodes, you
> would need a rather sizeable cache with at least 20k cachelines to have
> an impact. Noone does. So for all practical purposes, every single
> lookup will go to main memory.
>
> Maybe it is about time to suggest trying logfs?
What's the status of logfs on NAND ?
Last time I check, it didn't manage badblock.
Matthieu
next prev parent reply other threads:[~2008-01-21 15:59 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-17 16:12 Jffs2 and big file = very slow jffs2_garbage_collect_pass Matthieu CASTET
2008-01-17 16:26 ` Jörn Engel
2008-01-17 17:43 ` Josh Boyer
2008-01-18 9:39 ` Matthieu CASTET
2008-01-18 12:48 ` Josh Boyer
2008-01-18 16:17 ` Matthieu CASTET
2008-01-18 17:55 ` Josh Boyer
2008-01-18 18:17 ` Jörn Engel
2008-01-21 15:57 ` Matthieu CASTET [this message]
2008-01-21 21:25 ` Jörn Engel
2008-01-21 22:16 ` Josh Boyer
2008-01-21 22:29 ` Jörn Engel
2008-01-22 8:57 ` Matthieu CASTET
2008-01-22 12:03 ` Jörn Engel
2008-01-22 13:24 ` Ricard Wanderlof
2008-01-22 15:05 ` Jörn Engel
2008-01-23 9:23 ` Ricard Wanderlof
2008-01-23 10:19 ` Jörn Engel
2008-01-23 10:41 ` Ricard Wanderlof
2008-01-23 10:57 ` Jörn Engel
2008-01-23 11:57 ` Ricard Wanderlof
2008-01-23 13:01 ` Jörn Engel
2008-01-23 13:16 ` Ricard Wanderlof
2008-01-23 14:06 ` Jörn Engel
2008-01-23 14:25 ` Ricard Wanderlof
2008-01-21 22:36 ` Glenn Henshaw
2008-01-18 17:20 ` Glenn Henshaw
2008-01-18 18:39 ` Jamie Lokier
2008-01-18 21:00 ` Jörn Engel
2008-01-19 0:23 ` Jamie Lokier
2008-01-19 2:38 ` Jörn Engel
2008-01-17 23:22 ` David Woodhouse
2008-01-18 9:45 ` Matthieu CASTET
2008-01-18 18:20 ` Jamie Lokier
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