Question about BITSET_WORD

[Brian Paul]

Maybe there should be a comment regarding the performance and risk of 
change?

-Brian

On 8/21/24 07:54, Faith Ekstrand wrote:
> I've actually benchmarked this and 32bit is still faster on many 
> modern CPUs.
>
> Also, I would be very surprised if we could change it without breaking 
> the universe. I'm sure there are hard-coded 32s various places.
>
> ~Faith
>
> On Wed, Aug 21, 2024 at 8:13 AM Christophe JAILLET 
> <christophe.jaillet at wanadoo.fr> wrote:
>
>     Hi,
>
>     I'm new to this list, so sorry if it is not the correct place.
>
>     I've started to looked at the source code of mesa and I wonder why in
>     src/util/bitset.h we have:
>
>          #define BITSET_WORD unsigned int
>
>     This is as-is since at least 2015, probably 2011.
>
>     Would it make sense to have it as a long, at least on 64 bits arch?
>     (the linux kernel uses bitmaps as unsigned long)
>
>     I don't think that it should be a noticeable speed-up, but at
>     least on
>     Linux it could save some cycles when doing some OR or AND and co on
>     bitmaps on a 64 bits cpu.
>
>     Just my 2c.
>
>     Christophe JAILLET
>

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