On Sun, Jul 22, 2012 at 11:28:51PM -0700, Marc MERLIN wrote:
> On Sun, Jul 22, 2012 at 11:47:57PM +0200, Arno Wagner wrote:
> > On Sun, Jul 22, 2012 at 01:39:29PM -0700, Marc MERLIN wrote:
> > > On Sun, Jul 22, 2012 at 09:47:32PM +0200, Yves-Alexis Perez wrote:
> > > > > Any suggestions would be appreciated.
> > > >
> > > > I'm using Debian sid (so still at 3.2 kernel), currently using a 256G
> > > > Samsung SSD. What I get is:
> >
> > SID? That would be "unstable", whit possible assorted problems.
Ok, sorry for my confusion, what kernel/distro are you running?
[...]
> > Maybe AES-NI needs very long for something it needs to do each
> > sector. Google("aes-ni slow") found at least some indications that
> > aes-ni may still have problems.
>
> It was worth a shot, thanks for the suggestion.
>
> gandalfthegreat:~# lsmod | grep aes
> aes_x86_64 16796 34
> gandalfthegreat:~# hdparm -t -T /dev/mapper/cryptroot
>
> /dev/mapper/cryptroot:
> Timing cached reads: 15802 MB in 2.00 seconds = 7909.98 MB/sec
> Timing buffered disk reads: 68 MB in 3.04 seconds = 22.39 MB/sec
> gandalfthegreat:~#
>
> Unfortunately, speed is exactly the same.
>
> with aes_x86_64:
> gandalfthegreat:/var/local/VirtualBox VMs/w2k_virtual# dd if=test of=/dev/null
> 4192640+0 records in
> 4192640+0 records out
> 2146631680 bytes (2.1 GB) copied, 12.4848 s, 172 MB/s
>
> I then rebooted with aesni_intel and got this:
> gandalfthegreat:/var/local/VirtualBox VMs/w2k_virtual# dd if=test of=/dev/null
> 4192640+0 records in
> 4192640+0 records out
> 2146631680 bytes (2.1 GB) copied, 8.42506 s, 255 MB/s
That does not seem to be it.
> So those speeds are expected/believable, but I still don't know why
> hdparm is so slow on /dev/mapper/cryptroot.
>
> Mmmh....
Indeed.
Arno
--
Arno Wagner, Dr. sc. techn., Dipl. Inform., Email: arno@xxxxxxxxxxx
GnuPG: ID: 1E25338F FP: 0C30 5782 9D93 F785 E79C 0296 797F 6B50 1E25 338F
----
One of the painful things about our time is that those who feel certainty
are stupid, and those with any imagination and understanding are filled
with doubt and indecision. -- Bertrand Russell
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