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From: Pekka Enberg <penberg@kernel.org>
To: Prasad Joshi <prasadjoshi124@gmail.com>
Cc: mingo@elte.hu, kvm@vger.kernel.org, asias.hejun@gmail.com,
	gorcunov@gmail.com, levinsasha928@gmail.com,
	chaitanyakulkarni15@gmail.com, ashwini.kulkarni@gmail.com,
	anupshendkar@gmail.com
Subject: Re: [PATCH v3] kvm tools: Add QCOW level2 caching support
Date: Fri, 03 Jun 2011 00:07:59 +0300	[thread overview]
Message-ID: <1307048879.27309.3.camel@jaguar> (raw)
In-Reply-To: <BANLkTim-KES-u2WRpsQTWTEYWjNMFsnCig@mail.gmail.com>

On Thu, 2011-06-02 at 21:57 +0100, Prasad Joshi wrote:
> > Assuming the data is just mixed up, I'm not completely happy that
> > we're making random seeks almost 5% slower. Any ideas why that's
> > happening?
> 
> Yes they are mixed.
> 
> I am assuming, probably delay while caching.

That doesn't make sense to me. Why would "caching delay" be
significantly slower than the non-cached version where we do full read
all the time? Maybe I didn't quite understand the code but that sounds
like a bug lurking somewhere in the caching code - maybe we cache too
much or something?

			Pekka


  reply	other threads:[~2011-06-02 21:08 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-02 20:01 [PATCH v3] kvm tools: Add QCOW level2 caching support Prasad Joshi
2011-06-02 20:37 ` Pekka Enberg
2011-06-02 20:57   ` Prasad Joshi
2011-06-02 21:07     ` Pekka Enberg [this message]
2011-06-02 21:11 ` Pekka Enberg
2011-06-02 21:19 ` Sasha Levin
2011-06-03  5:56   ` Pekka Enberg
2011-06-03  7:15     ` Ingo Molnar
2011-06-03  7:23       ` Pekka Enberg

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