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Ken Giusti resolved DISPATCH-1372. ---------------------------------- Resolution: Implemented Assignee: Ken Giusti Fix Version/s: 1.9.0 > alloc_pool intrusive linked list can be replaced by a linked stack > ------------------------------------------------------------------ > > Key: DISPATCH-1372 > URL: https://issues.apache.org/jira/browse/DISPATCH-1372 > Project: Qpid Dispatch > Issue Type: Improvement > Components: Routing Engine > Affects Versions: 1.8.0 > Reporter: Francesco Nigro > Assignee: Ken Giusti > Priority: Major > Fix For: 1.9.0 > > Attachments: DOOM-3-BFG-Technical-Note.pdf, > image-2019-06-21-11-08-17-015.png, image-2019-06-21-11-09-02-228.png, > linked_list_misses.svg, stack_list_misses.svg > > > alloc_pool is currently using a intrusive linked list approach to reduce the > need of external data structures to hold data, saving expensive pointer > chasing, but on modern architectures the data dependency between a current > node and next/prev prevent the CPU prefetcher to stream nodes speculatively. > There are different approaches that could benefit of prefetcing, but need to > decouple the data stored from its container eg a linked stack. > A linked stack is composed by doubly-linked chunks (allocated lazily) that > make possible for the CPU to prefetch next/prev pointers given that those are > already contained in the current chunk (if any). > Although it seems counter-intuitive (given that introduce 1 more hop to reach > the data), such data-structure is much more cache-friendly on modern > architectures: I will attach some cache misses analysis to show it. > -- This message was sent by Atlassian JIRA (v7.6.14#76016) --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@qpid.apache.org For additional commands, e-mail: dev-h...@qpid.apache.org