[jira] [Commented] (BOOKKEEPER-964) Add concurrent maps and sets for primitive types

["ASF GitHub Bot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/BOOKKEEPER-964?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15766623#comment-15766623 ] 

ASF GitHub Bot commented on BOOKKEEPER-964:
-------------------------------------------

GitHub user eolivelli opened a pull request:

    https://github.com/apache/bookkeeper/pull/96

    BOOKKEEPER-964 Ignore findbugs warnings

    

You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/eolivelli/bookkeeper BOOKKEEPER-964-findbugs

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/bookkeeper/pull/96.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

    This closes #96
    
----
commit 3104c6fafcdafc208b7302fd3080f41a72a060a0
Author: eolivelli <eo...@gmail.com>
Date:   2016-12-21T09:46:30Z

    Ignore findbugs warnings

----


> Add concurrent maps and sets for primitive types
> ------------------------------------------------
>
>                 Key: BOOKKEEPER-964
>                 URL: https://issues.apache.org/jira/browse/BOOKKEEPER-964
>             Project: Bookkeeper
>          Issue Type: Improvement
>            Reporter: Matteo Merli
>            Assignee: Matteo Merli
>             Fix For: 4.5.0
>
>
> In BookKeeper there are many instances of maps and sets that use ledger id
> and entry ids as keys or values. JDK concurrent collections have the overhead
> of boxing all the primitive values into objects (eg: long --> Long) that would
> need to be allocated from the heap. In addition to that, JDK map implementations
> are closed hash tables and they will require at least one more allocation to hold
> the linked-list/tree node.
> There are already available libraries that offer primitive collections with
> zero-allocation, but none of these support concurrent maps/sets.
> We have added a handful of specializations, all based on the same implementation
> idea. We have a hash table which is broken down into multiple sections. Each
> sections, on its own, is an open hash table with linear probing, protected by
> a stamped lock.
> All insertions, lookups and iterations on these collections are allocation free.
> {noformat}
> ConcurrentLongHashMap: Map<long, Object>
> ConcurrentLongHashSet: Set<long>
> ConcurrentLongLongHashMap: Map<long, long>
> ConcurrentLongLongPairHashMap: Map< Pair<long, long>, Pair<long, long> >
> ConcurrentOpenHashMap: Map<Object, Object>
> ConcurrentOpenHashSet: Set<Object>
> {noformat}



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)