[FFmpeg-devel] [PATCH] avcodec/dsddec: add slice threading support

[Paul B Mahol]

On Thu, Aug 1, 2019 at 3:56 AM David Bryant <david at wavpack.com> wrote:

>
> On 7/30/19 1:43 AM, Carl Eugen Hoyos wrote:
> > Am So., 28. Juli 2019 um 23:35 Uhr schrieb Paul B Mahol <
> onemda at gmail.com>:
> >> Hi,
> >>
> >> patch attached.
> > As just posted on irc:
> > On an 8-core Intel cpu, this makes decoding slower by a factor two,
> > heating the cpu
> > ten times as much, on a multi-core powerpc, decoding is nearly two
> > times slower, and
> > heats nearly eight times as much.
>
> I can verify the greatly increased CPU load on a dual core system also. I
> also verified that the outputted audio data is correct
> (identical to unmodified code) and that there are no more samples being
> processed, indicating it's probably just threading overhead.
>
> The dsd2pcm conversion is pretty optimized and I suspect that's just way
> too fast to be worth multi-threading.
>

It appears it is not, see new patches.
As suspected using uint8s and unaligned bufer for stuff leads to big
slowdown when multi-threading.


>
> As I suggested earlier, it's the DST decompression that is worth looking
> into for threading.
>
> -David
>
>
> >
> > Carl Eugen
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>
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