[jira] [Created] (MIME4J-323) About MimeTokenStream usage of LinkedList

["Benoit Tellier (Jira)" <mi...@james.apache.org>]

Benoit Tellier created MIME4J-323:
-------------------------------------

             Summary: About MimeTokenStream usage of LinkedList
                 Key: MIME4J-323
                 URL: https://issues.apache.org/jira/browse/MIME4J-323
             Project: James Mime4j
          Issue Type: Improvement
          Components: core
            Reporter: Benoit Tellier


A defacto programming MOJO around is that linked list is bad: overhead of allocating bi-directional pointers, bad cache locality, etc... The benefits are low compared to precised arrays that are a better de-facto choice.

Now see attached a flame graph from James showing 2% of its allocation, and 18.7 of memory allocations of that parsing use case. See attached flame graph.

I benchmarked ArrayDeque usage locally and it was shlightly faster (in the ms range) and allocated ~1KB less per message:

{code:java}
BEFORE
    JMHLongMultipartReadBench.benchmark1                                      avgt    5      39.842 ±    1.820   us/op
    JMHLongMultipartReadBench.benchmark1:·gc.alloc.rate.norm                  avgt    5   19448.003 ±    0.001    B/op

AFTER
    JMHLongMultipartReadBench.benchmark1                               avgt    5     38.687 ±   2.935   us/op
    JMHLongMultipartReadBench.benchmark1:·gc.alloc.rate.norm           avgt    5  18128.003 ±   0.001    B/op

{code}






--
This message was sent by Atlassian Jira
(v8.20.10#820010)