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From: Milan Broz <mbroz@redhat.com>
To: Nikolay Kichukov <hijacker@oldum.net>
Cc: dm-crypt@saout.de, Peter Merhaut <petermerhaut@gmail.com>
Subject: Re: [dm-crypt] slow read performance, but fast writes?
Date: Thu, 15 Sep 2011 12:45:40 +0200	[thread overview]
Message-ID: <4E71D754.2050506@redhat.com> (raw)
In-Reply-To: <4E71CA41.1060808@oldum.net>


On 09/15/2011 11:49 AM, Nikolay Kichukov wrote:
> Hi,
> this query is best suited for md-raid mailing list as what you measure:
> 
> dd if=/dev/md3 of=/dev/null bs=1M
> 
> does not involve any decryption. You are reading directly from the md device and there is no matter what is actually there.

heh. I read that as crypt device and it is MD directly, sorry for confusion.
Seems my brain is still in different timezone :)

yes, this test has nothing to do with crypt.

Anyway, it is interesting that the problem is there even without crypt,
perhaps you should ask on linux-raid list then.

for badblock - I guess it just submits all IO from one cpu,
so only one core is used for encryption in fact. There applies the same what I wrote before.

Milan

  parent reply	other threads:[~2011-09-15 10:45 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-14 14:04 [dm-crypt] slow read performance, but fast writes? Peter Merhaut
2011-09-14 15:04 ` Arno Wagner
2011-09-14 16:47   ` Peter Merhaut
2011-09-15  9:49     ` Nikolay Kichukov
2011-09-15  9:53       ` Peter Merhaut
2011-09-15 10:45       ` Milan Broz [this message]
2011-09-15 11:07         ` Peter Merhaut
2011-09-14 15:15 ` Milan Broz

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