[
https://issues.apache.org/jira/browse/HBASE-13259?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Zee Chen updated HBASE-13259:
-----------------------------
Attachment: mmap-0.98-v1.patch
> mmap() based BucketCache IOEngine
> ---------------------------------
>
> Key: HBASE-13259
> URL: https://issues.apache.org/jira/browse/HBASE-13259
> Project: HBase
> Issue Type: New Feature
> Components: BlockCache
> Affects Versions: 0.98.10
> Reporter: Zee Chen
> Attachments: mmap-0.98-v1.patch
>
>
> Of the existing BucketCache IOEngines, FileIOEngine uses pread() to
> copy data from kernel space to user space. This is a good choice when the
> total working set size is much bigger than the available RAM and the latency
> is dominated by IO access. However, when the entire working set is
> small enough to fit in the RAM, using mmap() (and subsequent memcpy()) to
> move data from kernel space to user space is faster. I have run some short
> keyval gets tests and the results indicate a reduction of 2%-7% of kernel CPU
> on my system, depending on the load. On the gets, the latency
> histograms from mmap() are identical to those from pread(), but peak
> throughput is close to 40% higher.
> This patch modifies ByteByfferArray to allow it to specify a backing file.
> Example for using this feature: set hbase.bucketcache.ioengine to
> mmap:/dev/shm/bucketcache.0 in hbase-site.xml.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
