DM-Crypt Archive on lore.kernel.org
 help / color / mirror / Atom feed
From: "André Gall" <dm-crypt@andregall.de>
To: dm-crypt@saout.de
Subject: Re: [dm-crypt] aes-xts-plain with aes_x86_64 makes my SSD 5x slower than my encrypted HD
Date: Mon, 23 Jul 2012 19:27:47 +0200	[thread overview]
Message-ID: <500D8993.7030802@andregall.de> (raw)
In-Reply-To: <500D3776.2000307@redhat.com>

I remember a test which I conducted after I received my Intel SDD 510 
120 GB about 1 year ago. I don't remember all the details, but the 
essence was that write speed decreased dramatically if the write process 
wasn't aligned.

I did:
dd if=/dev/zero of=/dev/sda bs=4k
I got around 400 Mb/sec, which was expected. But when I did:

dd if=/dev/zero of=/dev/sda bs=5k
I got only around 40 Mb/sec

When you write in 5k blocks, the SSD has to do a lot of overhead because 
of the Read-Modify-Write operations. I guess this might also be the case 
if you write in 4k blocks, but don't align them to the SSD's "native" 
blocks. So I would check for any misalignment.

Regards,
André

  parent reply	other threads:[~2012-07-23 17:37 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-22 19:07 [dm-crypt] aes-xts-plain with aes_x86_64 makes my SSD 5x slower than my encrypted HD Marc MERLIN
2012-07-22 19:47 ` Yves-Alexis Perez
2012-07-22 20:39   ` Marc MERLIN
2012-07-22 21:47     ` Arno Wagner
2012-07-23  6:07       ` Yves-Alexis Perez
2012-07-23  6:28       ` Marc MERLIN
2012-07-23  8:14         ` Arno Wagner
2012-07-23 10:46           ` Milan Broz
2012-07-23 11:09             ` Yves-Alexis Perez
2012-07-23 11:37               ` Milan Broz
2012-07-23 15:08                 ` André Gall
2012-07-23 17:27                 ` André Gall [this message]
2012-07-24 14:06             ` Heinz Diehl
2012-07-24 14:16               ` Milan Broz
2012-07-23 16:12           ` Marc MERLIN
2012-07-23 16:19             ` Yves-Alexis Perez
2012-07-23 17:54               ` Marc MERLIN
2012-07-23 19:26                 ` Yves-Alexis Perez
2012-07-23 17:15             ` Milan Broz
2012-07-23 17:51               ` Marc MERLIN
2012-07-23 21:31                 ` Milan Broz
2012-07-24  5:57                   ` Marc MERLIN
2012-07-24  6:25                     ` Heinz Diehl
2012-07-24 15:02                       ` Marc MERLIN
2012-07-24 15:19                         ` Milan Broz
2012-07-24 16:09                           ` Marc MERLIN
2012-07-24 13:54                     ` Milan Broz
     [not found]                       ` <500E9099.8050501@redhat.com>
2012-07-24 14:27                       ` Heinz Diehl
2012-07-24 14:58                         ` Heinz Diehl
2012-07-24 15:38                           ` Marc MERLIN
2012-07-24 16:48                             ` Heinz Diehl
2012-07-24  6:11                   ` Heinz Diehl
2012-07-22 21:55     ` Marc MERLIN
2012-07-22 20:22 ` Heinz Diehl
2012-08-12 12:49 ` Pasi Kärkkäinen
2012-08-16  7:43   ` Marc MERLIN
     [not found]     ` <502D1F96.3080905@andregall.de>
2012-08-16 17:57       ` Marc MERLIN

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=500D8993.7030802@andregall.de \
    --to=dm-crypt@andregall.de \
    --cc=dm-crypt@saout.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox