OpenSSH performance with VIA padlock

Jan Klod janklodvan at
Wed Nov 19 06:21:28 EST 2008

On Tuesday 18 November 2008 18:47:58 you wrote:
> On Tue, Nov 18, 2008 at 17:28:11 +0200, Jan Klod wrote:
> > Hello list,
> > please spend a minute considering these facts and maybe there is
> > something to improve:
> >
> > 1) VIA Eden based board can write AES256 encrypted information on HDD at
> > > 60MB/s
Yes, this one I am very sure about. Padlock was used in that case!

> > 2) iperf shows NIC speed 69MB/s
> > 3) openssl tests have even better results
> > 4) openssh can transfer AES256 encrypted information at < 27MB/s (and
> > worse with HDD encryption)
> >
> > It is better with openssh 5.x, than 4.6, but still I see no reason why
> > results are so bad... Please, could someone explain? I don't believe,
> > padlock is used properly...
> >
> > Jan
> Remember, cycles are also taken up by the message digest. You don't
> mention which MAC you are using nor do you give any of the OpenSSL speed
> numbers for AES or any of the digests.
> Also, what performance do you get for a memory-to-memory transfer over
> the loopback?

mount -t ramfs ramfs /mnt/ram0
mount -t ramfs ramfs /mnt/ram1
dd if=/dev/sda of=/mnt/ram0/1 bs=512K count=400
400+0 records in
400+0 records out
209715200 bytes (210 MB) copied, 3.37567 s, 62.1 MB/s

dd if=/mnt/ram0/1 of=/mnt/ram1/1 bs=512K count=400
400+0 records in
400+0 records out
209715200 bytes (210 MB) copied, 1.31667 s, 159 MB/s

scp -c aes256-cbc -o MACs=hmac-md5 /mnt/del VIA:/mnt
100%  200MB  22.2MB/s

scp -c aes256-cbc -o MACs=hmac-sha1 /mnt/del VIA:/mnt
100%  200MB  18.2MB/s

scp -c aes256-cbc -o MACs=hmac-sha1-96 /mnt/del VIA:/mnt
100%  200MB  18.2MB/s

Those scp speeds are becoming slower as transfers are lasting longer, though. 
That is a final value. Since md5, which is not supported by VIA padlock is 
faster than sha1 (which is said to be supported), it is more than suspicios, 
that hardware accelerator is not used...

zcat /proc/config.gz | grep PADLOCK

openssl speed:
The 'numbers' are in 1000s of bytes per second processed.
type             16 bytes     64 bytes    256 bytes   1024 bytes   8192 bytes
md5               4335.51k    15169.19k    43828.91k    82976.77k   112391.51k
hmac(md5)         5269.63k    17989.14k    49426.43k    87639.72k   113415.51k
sha1              3996.45k    12144.02k    28099.67k    41740.97k    48594.07k
sha256            2486.99k     5744.75k    10174.81k    12615.68k    13537.21k
sha512            1755.15k     7005.40k    12058.54k    18123.09k    21217.55k
aes-128 cbc      12835.45k    16641.41k    18044.67k    18433.37k    18512.29k
aes-192 cbc      11315.21k    14180.52k    15334.57k    15637.16k    15742.29k
aes-256 cbc      10224.77k    12465.86k    13237.33k    13445.46k    13480.06k

Well... I was wrong saying, that I have openssl aes HW accel. working. 

I am using 2.6.25 kernel with PaX, no other patches. Please, do you have any 
idea at this point, why padlock is not used? What should I try?

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