Re: patch: multiple-request, async-request support for /dev/crypto

I have to say it looks great - excellent for high-performance
application designs with single-threaded event-driven models.
Multi-threaded apps would benefit too.

I may be a tiny bit biased having written part of it ;-).

Darran Hunt.


On 27/03/2008, at 7:13 PM, Thor Lancelot Simon wrote:

> The attached patch adds ioctls for multiple request submission and
> retrieval in a single system call, and for asynchronous operation via
> select()/poll() to /dev/crypto.  It was written for a slightly older
> NetBSD-current and I've hastily adapted it to Andrew's recent file
> descriptor allocation changes, which I hope I got right -- it's well
> tested before that adaptation but untested with it (caveat emptor).
>
> With this patch and a slightly clever multithreaded application that
> batches requests when pushing them to /dev/crypto we can do 84,000
> trivial asymmetric operations/sec (32 bit modular math ops) to a
> rather old crypto accellerator card, with a Core 2 Duo as the host.
> I think it's worth the added complexity.  Even simpler applications
> can benefit -- a lot -- from async operation and retrieving multiple
> requests at once when poll() fires.
>
> There is some duplicated code here in the multiple-request ioctls that
> could be shared with the single-request ioctls.  It'd be a moderate  
> pain
> to clean up and I'd prefer to do that after commit so I can get this
> in the tree while I have time to focus on it.  Also, there is a large
> comment here describing the new ioctls and parameters which text I'll
> reproduce in or move to the manual page.
>
> I will revise the openssl engine to work as efficiently as possible  
> with
> the new ioctls added here once I sort out some issues about updating
> OpenSSL itself in our tree and feeding changes back to the OpenSSL  
> project
> in an effective way.
>
> Comments?
>
> -- 
> Thor Lancelot Simon
> Coyote Point Systems, Inc.			<[email protected]>
> Millerton, NY, USA<oc-multi.diff>