[CASSANDRA-9468] Improvements to BufferPool

• Type: Improvement
• Status: Open
• Priority: Low
• Resolution: Unresolved
• Fix Version/s: 5.x
• Component/s: Legacy/Core
• Assignee: Unassigned
• Reporter: Benedict Elliott Smith
• Created: 24/May/15 07:45
• Updated: 07/Mar/23 10:54

Description

Following up from CASSANDRA-8897, there are further improvements that can be made to the BufferPool:

1. The common code paths can be made non-atomic.
2. The chunk pool can be turned into a Stack, instead of a Queue, to improve the likelihood of cache presence
3. The chunk pool can be made processor-local, using e.g. https://github.com/OpenHFT/Java-Thread-Affinity
4. We can support smaller allocations by creating micro-chunks within each local pool, by allocating a single unit from the current chunk (or multiple units if we're about to discard a chunk that is not fully utilised).
   • It should be possible to generalise this approach to make the entire allocation stack tiered, so that whenever you want a new chunk you go to the parent chunk that is an order of magnitude larger, and allocate a small slice (which you convert into a Chunk). Slices below a certain size can be taken exclusive ownership of, and above a certain size they remain shared.

Issue Links

• is related to: CASSANDRA-8897 Remove FileCacheService, instead pooling the buffers