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Re: bitpack search in bitsets
From: |
Akim Demaille |
Subject: |
Re: bitpack search in bitsets |
Date: |
Fri, 20 Nov 2020 06:38:10 +0100 |
Hi Bruno,
> Le 18 nov. 2020 à 10:53, Bruno Haible <bruno@clisp.org> a écrit :
>
>> Conversely: couldn't ssfmalloc sit on top of bitset?
>
> Well, in ssfmalloc it is important to use the available space well. When
> I use a bitset of 256 bits in order to describe which of the 16-byte blocks
> of a 4096-bytes page are free, this requires 8 32-bit words. Now adding
> 5 (32-bit or 64-bit) words as meta-information, as defined per these
> type definitions: [...]
> is not really desirable. It would be only 1% waste, but the percents add up.
>
> In other words, the 'bitset' module - while generally good for applications -
> is one level too complex for this particular use-case.
It makes a lot of sense. Thanks for explaining!
Cheers.