[
https://issues.apache.org/jira/browse/CASSANDRA-8630?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14726545#comment-14726545
]
Stefania commented on CASSANDRA-8630:
-------------------------------------
Fixed a small problem that was causing CI issues and now CI is stable again:
http://cassci.datastax.com/job/stef1927-8630-3.0-testall/lastBuild/testReport/
http://cassci.datastax.com/job/stef1927-8630-3.0-dtest/lastBuild/testReport/
Relaunched cperf test with this fix in, see
[here|http://cstar.datastax.com/tests/id/0000ebe0-510f-11e5-a17a-42010af0688f].
The test I launched yesterday shows only a small difference in read ops, not
sure if related.
My request on IRC to set-up Windows CI must have gone unnoticed;
[~philipthompson] would you be able to set up CI on Windows for this branch?
> Faster sequential IO (on compaction, streaming, etc)
> ----------------------------------------------------
>
> Key: CASSANDRA-8630
> URL: https://issues.apache.org/jira/browse/CASSANDRA-8630
> Project: Cassandra
> Issue Type: Improvement
> Components: Core, Tools
> Reporter: Oleg Anastasyev
> Assignee: Stefania
> Labels: compaction, performance
> Fix For: 3.x
>
> Attachments: 8630-FasterSequencialReadsAndWrites.txt, cpu_load.png,
> flight_recorder_001_files.tar.gz, flight_recorder_002_files.tar.gz,
> mmaped_uncomp_hotspot.png
>
>
> When node is doing a lot of sequencial IO (streaming, compacting, etc) a lot
> of CPU is lost in calls to RAF's int read() and DataOutputStream's write(int).
> This is because default implementations of readShort,readLong, etc as well as
> their matching write* are implemented with numerous calls of byte by byte
> read and write.
> This makes a lot of syscalls as well.
> A quick microbench shows than just reimplementation of these methods in
> either way gives 8x speed increase.
> A patch attached implements RandomAccessReader.read<Type> and
> SequencialWriter.write<Type> methods in more efficient way.
> I also eliminated some extra byte copies in CompositeType.split and
> ColumnNameHelper.maxComponents, which were on my profiler's hotspot method
> list during tests.
> A stress tests on my laptop show that this patch makes compaction 25-30%
> faster on uncompressed sstables and 15% faster for compressed ones.
> A deployment to production shows much less CPU load for compaction.
> (I attached a cpu load graph from one of our production, orange is niced CPU
> load - i.e. compaction; yellow is user - i.e. not compaction related tasks)
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
