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From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: "Theodore Ts'o" <tytso@mit.edu>
Cc: linux-ext4@vger.kernel.org
Subject: Re: e2fsck readahead speedup performance report
Date: Fri, 8 Aug 2014 21:06:34 -0700	[thread overview]
Message-ID: <20140809040634.GL11191@birch.djwong.org> (raw)
In-Reply-To: <20140809035646.GA23604@thunk.org>

On Fri, Aug 08, 2014 at 11:56:46PM -0400, Theodore Ts'o wrote:
> Interesting results!
> 
> I noticed that the 1TB SSD did seem to suffer when you went from
> multi-threaded to single-threaded.  Was this a SATA-attached or
> USB-attached SSD?  And any insights about why the SSD seemed to
> require threading for better performance when using readaead?

PCIE, and it might simply be having issues. :/

One thing I haven't looked into is how exactly the kernel maps IO
requests to queue slots -- does each CPU get its own pile of slots to
use up?  I _think_ it does, but it's been a few months since I poked
at mq.  Hmm... max_sectors_kb=128, which isn't unusually odd.  Guess
I'll keep digging.

The other disks seems fairly normal, at least.

--D
> 
> 						- Ted
> --
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      reply	other threads:[~2014-08-09  4:06 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-08-09  3:18 e2fsck readahead speedup performance report Darrick J. Wong
2014-08-09  3:22 ` Darrick J. Wong
2014-08-09  3:56 ` Theodore Ts'o
2014-08-09  4:06   ` Darrick J. Wong [this message]

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