Re: [Ocf-linux-users] Benchmarking issues

[David M. <dav...@mc...>]

Jivin "Adam Cécile (Le_Vert)" lays it down ...
> On 01/09/2011 13:54, David McCullough wrote:
> > Jivin "Adam C??cile (Le_Vert)" lays it down ...
> >> Hello OCF guys,
> >>
> >> I'm trying to enable ocf on a Geode LX cpu wich is known to handle
> >> aes-128-cbc trhough geode-aes kernel module.
> >> I rebuilt linux-3.0 with OCF kernel patch and then rebuilt openssl
> >> debian's package with -DHAVE_CRYPTODEV -I$(CURDIR)/debian/includes (this
> >> directory contains crypto/cryptodev.h)
> >> Then I loaded ocf, cryptosoft and cryptodev kernel modules...
> >>
> >> Here is the result of my tests using different cipher:
> >>
> >> # With OpenSSL 1.0.0d cryptodev enabled package
> >> # openssl speed -evp<cipher>
> >> aes-128-cbc      16761.07k    58822.40k   240275.91k   547942.40k
> >> 3126886.40k
> >> bf-cbc           13351.73k    67366.40k   191564.80k   715946.67k
> >> 1298432.00k
> >> des-ede3-cbc     30708.80k    88375.47k   186675.20k
> >> 415846.40k         infk
> >>
> >> #rmmod cryptodev
> >> aes-128-cbc       3595.73k     3942.16k     4062.50k     8154.89k
> >> 8244.06k
> >> bf-cbc            8260.17k    10052.27k    10728.30k    10923.12k
> >> 10929.06k
> >> des-ede3-cbc      1961.65k     2046.67k     2071.55k     2076.43k
> >> 2074.03k
> >>
> >> Results without cryptodev looks fine (slow 500Mhz CPU) but the ones with
> >> cryptodev loaded doesn't make any sense !
> >> There's no reason to have such faster blowfish and des results, as the
> >> hardware chip only handles aes-128-cbc.
> >> Could you please tell me what I'm doing wrong ???
> > Add the "-elapsed" option to openssl speed to get real numbers.
> > Otherwise it doesn't count kernel time IIRC,
> >
> > Cheers,
> > Davidm
> >
> Thanks, it looks a lot better now.
> 
> # With cryptodev loaded:
> # openssl speed -elapsed -evp aes-128-cbc
> aes-128-cbc        507.31k     1964.05k     7202.05k    19972.10k    
> 41997.65k
> bf-cbc             538.20k     1801.51k     4496.98k     7171.07k     
> 8672.60k
> des-ede3-cbc       410.43k      883.29k     1236.37k     1385.47k     
> 1436.33k
> 
> # Without cryptodev loaded
> aes-128-cbc       3580.90k     3929.60k     4037.89k     8096.77k     
> 8211.11k
> bf-cbc            8249.83k    10068.86k    10702.76k    10904.58k    
> 10944.51k
> des-ede3-cbc      1989.86k     2070.83k     2075.82k     2107.73k     
> 2106.51k
> 
> Is it normal than I have lower bandwitch with cryptodev when the size is 
> lower than 256 bytes ?

Yes,  it's the overhead of copying the data into the kernel and back out.
Smaller packets incurrs a higher % overhead per encrypted byte.

> Btw, cryptodev seems to be slower than regular openssl on non-hardware 
> accelerated cipher. Anyway to enable cryptodev ONLY for aes-128-cbc ?

Again,  its the overhead of copying the data to the kernel.  When you do
blowfish or similar in user space its the same code with no copies, for
cryptodev you need to copy the packet into the kernel,  run the cipher, and
copy it back, plus encryption setup time.

The situation where cryptodev pays off is when you have real crypto hardware
and a slow CPU, it frees up CPU time for other tasks and improves speed ;-)

There is currently no way to only have cryptodev to AES,  though all you
need to do is comment out the othe ciphers in cryptosoft and it will only
use cryptodev for AES then, the openssl code will automatically fall back to
internal crypto if cryptodev doesn't have support for an alg. ;-)

Cheers,
Davidm


-- 
David McCullough,      dav...@mc...,  Ph:+61 734352815
McAfee - SnapGear      http://www.mcafee.com         http://www.uCdot.org