Re: SLRU optimization - configurable buffer pool and partitioning the SLRU lock

On 2024-Feb-23, Andrey M. Borodin wrote:

> I'm sure anyone with multiple CPUs should increase, not decrease
> previous default of 128 buffers (with 512MB shared buffers). Having
> more CPUs (the only way to benefit from more locks) implies bigger
> transaction buffers.

Sure.

> IMO making bank size variable adds unneeded computation overhead, bank
> search loops should be unrollable by compiler etc.

Makes sense.

> Originally there was a patch set step, that packed bank's page
> addresses together in one array. It was done to make bank search a
> SIMD instruction.

Ants Aasma had proposed a rework of the LRU code for better performance.
He told me it depended on bank size being 16, so you're right that it's
probably not a good idea to make it variable.

-- 
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/