Re: define pg_structiszero(addr, s, r)
От | Bertrand Drouvot |
---|---|
Тема | Re: define pg_structiszero(addr, s, r) |
Дата | |
Msg-id | ZyiYzakU83uFMfX0@ip-10-97-1-34.eu-west-3.compute.internal обсуждение исходный текст |
Ответ на | Re: define pg_structiszero(addr, s, r) (Bertrand Drouvot <bertranddrouvot.pg@gmail.com>) |
Список | pgsql-hackers |
Hi, On Fri, Nov 01, 2024 at 12:50:10PM +0000, Bertrand Drouvot wrote: > Hi, > > On Fri, Nov 01, 2024 at 09:47:05PM +1300, David Rowley wrote: > > On Fri, 1 Nov 2024 at 20:49, Michael Paquier <michael@paquier.xyz> wrote: > > I've attached what I thought a more optimal version might look like in > > case anyone thinks making it better is a good idea. > > > > Thanks for the proposal! > > I like the idea, I think that's worth to add a few comments, something like: > > 1 === > > + while (((uintptr_t) p & (sizeof(size_t) - 1)) != 0) > > Add a comment like "Checks bytes, byte by byte, until the pointer is aligned"? > > 2 === > > + for (; p < aligned_end; p += sizeof(size_t)) > > Add a comment like "Multiple bytes comparison(s) at once"? > > 3 === > > + while (p < end) > + { > > Add a comment like "Compare remaining bytes, byte by byte"? > > 4 === > > Out of curiosity I did test your proposal and it performs well (see [0]) for > the PageIsVerifiedExtended() case. Also, 5 === Shouldn't we handle the cases where ptr is NULL and/or len == 0? (should probably have already been done in the current version of pg_memory_is_all_zeros() though). Regards, -- Bertrand Drouvot PostgreSQL Contributors Team RDS Open Source Databases Amazon Web Services: https://aws.amazon.com
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