Re: [PATCH 1/4] md: Factor out RAID6 algorithms into lib/

H. Peter Anvin
2009-07-29T18:20:58Z

On 07/18/2009 11:52 AM, Alex Elsayed wrote:
> Alex Elsayed wrote:
>
>> H. Peter Anvin wrote:
>>> implementation in Java, called "Jerasure".) Implementability using real
>>> array instruction sets is key to decent performance.
>> Actually, it is made clear in the paper that Jerasure is written as a C
>> library, and Clearsafe is the only Java implementation. Don't let the name
>> fool you. ;D
> And again, I make a typo. s/Clearsafe/Cleversafe/.
>

It's still their own implementation of poor quality. That it is poor
quality shows in the numbers, which are dramatically lower than the
actual Linux implementation -- by an order of magnitude or more. In
other words, they build a strawman and knock it down.

The actual Linux implementation blasts any of the numbers they have in
their paper, which I presume means they haven't optimized any of them.
As such, all the numbers are meaningless.

-hpa