Re: [FFmpeg-devel] [PATCH] lavc/vc1dsp: R-V V mspel_pixels

[flow gg <hlefthleft@gmail.com>]

Hi, I got BananaPi F3, made some fixes, updated in reply

Rémi Denis-Courmont <remi@remlab.net> 于2024年5月6日周一 03:26写道：

> Le sunnuntaina 5. toukokuuta 2024, 12.18.56 EEST flow gg a écrit :
> > > Does MF2 actually improve perfs over M1 here?
> >
> > The difference here seems very small, but when both mf2 and m1 are
> correct,
> > the test results have only shown mf2 to be better, so I want to use mf2.
>
> I can live with that. But this is a slippery slope because large vector
> sizes
> would involve even smaller fractions. Then we would need to compute the
> value
> which might negate the performance gains from fractional multipliers.
>
> The fastest approach that I can think of is a symbolic LA (which expands
> to
> 1xAUIPC + 1xLA) to load a precomputed VTYPE value from a static variable.
> Furthermore, this requires VSETVL, which precludes immediate constant VL
> Indeed, the VSETIVL instruction does not exist.
>
> AFAIU, BananaPi F3 has 256-bit vectors already now.
>
> --
> Rémi Denis-Courmont
> http://www.remlab.net/
>
>
>
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