Hi H. Peter,
H. Peter Anvin wrote:
>> We defined async_pq() function as hardware can do GF multiplication of
>> arbitrary elements and we want to take advantage of this fact. But by
>> the design of ASYNC_TX API we have to provide synchronous version of
>> that function too.
>>
>
> I don't think that makes sense since the algorithm doesn't use
> vector-vector multiplications and there is no need for them. As such,
> you're actively excluding support for hardware which only provides
> scalar-vector multiplication, even though that is all we need.
>
> In fact, vectorizing the constant doesn't make much sense.
Hm... I have to admit I can't understand your
vector-vector/scalar-vector terminology... What vector space are you
talking about?
async_gen_syndrome() takes element of GF^n(256) and returns result of
scalar multiplication of it with constant ({01}, {02}, {02}^2, ...,
{02}^n) vector.
async_pq() takes two vectors from GF^n(256) and returns their scalar
multiplication.
We need async_pq() function if we want to offload D_x = A * (P + P_{xy})
+ B * (Q + Q_{xy}) part of DD recovery and D_x = (Q + Q_x) * g^{-x} part
of DP recovery.
Regards, Ilya.
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
