Re: [PATCH 0/4] crypto: introduce generic dynamic software fallback and EIP93 support

[Herbert Xu]

On Tue, Jul 28, 2026 at 05:43:28PM +0900, Jihong Min wrote:
>
> The tcrypt AES-128-CBC results are median cycles from five runs. Lower
> is better. Disabled uses cbc(aes-eip93) directly, while enabled uses
> fallback(cbc(aes-eip93)).
> 
>   Request   Disabled   Enabled   Cycle reduction
>    (bytes)   (cycles)  (cycles)
>        16        322        18             94.4%
>        64        274        43             84.3%
>       128        292        74             74.7%
>       256        312       138             55.8%
>      1024        434       439             -1.2%
>      1424        492       488              0.8%
>      4096        980      1023             -4.4%

Do these results vary that much at run-time that requires a run-time
test? Surely you can predict the outcome for the platforms involved?

It appears to me that you're simply adding complexity for something
that can already be easily tuned by the administrator through the
algorithm priorities.

In fact, why not implement the benchmark in user-space and then based
on that result adjust the priorities?

Cheers,
-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt