Re: [Ocf-linux-users] OCF userland support

[David M. <Dav...@se...>]

Jivin Egor N. Martovetsky lays it down ...
> David,
> 
> I noticed that the throughput I get when using cryptotest or OpenSSL speed
> is much worse than what I get using ocf-bench.  I also don't get much
> improvement, if at all, when running mutiple threads of the above programs.

ocf-bench runs in kernel mode,  the data does not need to be
copied from user space to kernel space and back.  This make a massive
difference to performance.

All user apps need to pass their data through to the kernel and back.
Unfortunately we don't have a zero copy API for OCF (yet ;-)

Basically,  for OCF accelerated user space,  you need to be using larger
packets to help overcome the overheads of the user-kernel-user copies,
but it will never be a good as in-kernel crypto with a zero copy
interface.

> It seems that this is a result of using ioctl(vs unlocked_ioctl) to 
> access /dev/crypto, which
> would only allow one process doing crypto at a given time.  Is that a 
> known problem and
> are there plans to fix it?

I wasn't aware that ioctl would prevent multiple processes from working
in parallel.  I have seen performance improvements with multiple threads
on 2.4 systems.  Haven't checked on 2.6

> Also, is ocf-bench SMP safe?  I had to set CRYPTO_F_BATCH in the 
> crp_flags to make it work,
> otherwise with the CRYPTO_F_CBIMM it would not work in the SMP mode.

I have never thought nor checked that ocf-bench is SMP safe.  Which OCF
driver are you using when doing your tests ?  It could explain a few
things,

Cheers,
Davidm

-- 
David McCullough,  dav...@se...,   Ph:+61 734352815
Secure Computing - SnapGear  http://www.uCdot.org http://www.cyberguard.com