On Sun, Sep 01, 2024 at 07:24:03PM +0200, Christophe Leroy wrote:
> Without -O2, the generated code for testing chacha function is awful.
> GCC even implements rol32() as a function instead of just using the
> rotlwi instruction, that function is 20 instructions long.
> 
>       ~# time ./vdso_test_chacha
>       TAP version 13
>       1..1
>       ok 1 chacha: PASS
>       real    0m 37.16s
>       user    0m 36.89s
>       sys     0m 0.26s
> 
> Several other selftests directory add -O2, and the kernel is also
> always built with optimisation active. Do the same for vDSO selftests.
> 
> With this patch the time is reduced by approx 15%.
> 
>       ~# time ./vdso_test_chacha
>       TAP version 13
>       1..1
>       ok 1 chacha: PASS
>       real    0m 32.09s
>       user    0m 31.86s
>       sys     0m 0.22s
> 

Seems reasonable. I'll queue it up.

Thanks.

Jason

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