kern/178467: [request] Optimized Checksum Code for ZFS

[Xin Li]

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On 05/10/13 01:50, Steven Hartland wrote:
> The following reply was made to PR kern/178467; it has been noted
> by GNATS.
> 
> From: "Steven Hartland" <smh at freebsd.org> To:
> <bug-followup at freebsd.org>, <jkeller at bbiinternational.com> Cc: 
> Subject: Re: kern/178467: [request] Optimized Checksum Code for
> ZFS Date: Fri, 10 May 2013 09:47:59 +0100
> 
> We would need something more to go no than "looks like" I'm
> afraid.
> 
> Also Fletcher4 is the default checksum which achieves ~4GB/s per
> core in hashing performance, where as SHA-256 even with hand
> written assembly manages less than 1/10th that performance, so if
> your looking for performance for checksums use the default
> Fletcher4 instead of the SHA-256.
> 
> That said new processors do have HW support which could be used to
> accelerate SHA-256 support, details of this can be found here:- 
> http://download.intel.com/embedded/processor/whitepaper/327457.pdf
> 
> These sorts of core feature enhancements should be discussed and
> implemented upstream at illumos.

Speaking for this -- I'm thinking that maybe these could leverage some
sys/crypto facilities?  These would be also helpful for some other
kernel services like GELI, etc.

Cheers,
- -- 
Xin LI <delphij at delphij.net>    https://www.delphij.net/
FreeBSD - The Power to Serve!           Live free or die
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