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https://issues.apache.org/jira/browse/HADOOP-7446?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Todd Lipcon updated HADOOP-7446:
--------------------------------
Attachment: hadoop-7446.txt
New patch to fix up compilation issues on 32-bit:
The PIC workaround is only necessary on 32-bit PIC. If you try to use it on
64-bit PIC, you end up with a subtle bug: gcc may actually allocate the "ebx"
variable in the %ebx register, and then you end up getting the wrong result.
So, the fix is to only do the %ebx save off to the stack in 32-bit mode. See
http://www.technovelty.org/code/arch/pic-cas.html for a good explanation.
Given this, we now only worry about %ebx and not %rbx, since on 64-bit
platforms we don't have to save anything aside.
I've tested this code via TestDataChecksum on both 32-bit and 64-bit JVMs, and
also ran a short standalone test of the bulk_verify_crc32 under valgrind to
check for any possible memory errors.
> Implement CRC32C native code using SSE4.2 instructions
> ------------------------------------------------------
>
> Key: HADOOP-7446
> URL: https://issues.apache.org/jira/browse/HADOOP-7446
> Project: Hadoop Common
> Issue Type: Improvement
> Components: native
> Affects Versions: 0.23.0
> Reporter: Todd Lipcon
> Assignee: Todd Lipcon
> Fix For: 0.23.0
>
> Attachments: hadoop-7446.txt, hadoop-7446.txt, hadoop-7446.txt
>
>
> Once HADOOP-7445 is implemented, we can get further performance improvements
> by implementing CRC32C using the hardware support available in SSE4.2. This
> support should be dynamically enabled based on CPU feature flags, and of
> course should be ifdeffed properly so that it doesn't break the build on
> architectures/platforms where it's not available.
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