[jira] [Commented] (CASSANDRA-11519) Add support for IBM POWER

["Joshua McKenzie (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-11519?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15329700#comment-15329700 ] 

Joshua McKenzie commented on CASSANDRA-11519:
---------------------------------------------

[~ReiOdaira]: From [this link|https://www.ibm.com/developerworks/library/pa-dalign/]:
bq. On the other hand, modern PowerPC processors lack hardware support for unaligned 64-bit floating-point access. When asked to load an unaligned floating-point number from memory, modern PowerPC processors will throw an exception and have the operating system perform the alignment chores in software. Performing alignment in software is much slower than performing it in hardware.

So what I'm gathering is that there's a pretty significant hit on 64-bit unaligned accesses as they don't have hardware support on the platform. Do you have numbers to indicate that the unsafe.get* versions of accessors, unaligned w/processor exception, are preferable to the path the code takes w/unaligned false in Memory.java? 

> Add support for IBM POWER
> -------------------------
>
>                 Key: CASSANDRA-11519
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-11519
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Core
>         Environment: POWER architecture
>            Reporter: Rei Odaira
>            Assignee: Rei Odaira
>            Priority: Minor
>             Fix For: 2.1.x, 2.2.x, 3.0.x, 3.x
>
>         Attachments: 11519-2.1.txt, 11519-3.0.txt
>
>
> Add support for the IBM POWER architecture (ppc, ppc64, and ppc64le) in org.apache.cassandra.utils.FastByteOperations, org.apache.cassandra.utils.memory.MemoryUtil, and org.apache.cassandra.io.util.Memory.



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