You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@cassandra.apache.org by "Pavel Yaskevich (JIRA)" <ji...@apache.org> on 2014/04/29 23:43:15 UTC
[jira] [Commented] (CASSANDRA-6890) Standardize on a single read
path
[ https://issues.apache.org/jira/browse/CASSANDRA-6890?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13984840#comment-13984840 ]
Pavel Yaskevich commented on CASSANDRA-6890:
--------------------------------------------
mmap is better for the number of reasons but mostly because we have to do less syscalls and less copies (especially cross mode boundary). So I would, as well, vote to leave it and remove buffered I/O instead.
> Standardize on a single read path
> ---------------------------------
>
> Key: CASSANDRA-6890
> URL: https://issues.apache.org/jira/browse/CASSANDRA-6890
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Joshua McKenzie
> Assignee: Joshua McKenzie
> Labels: performance
> Fix For: 3.0
>
> Attachments: mmap_gc.jpg, mmap_jstat.txt, mmap_perf.txt, nommap_gc.jpg, nommap_jstat.txt
>
>
> Since we actively unmap unreferenced SSTR's and also copy data out of those readers on the read path, the current memory mapped i/o is a lot of complexity for very little payoff. Clean out the mmapp'ed i/o on the read path.
--
This message was sent by Atlassian JIRA
(v6.2#6252)