[jira] [Commented] (HADOOP-7446) Implement CRC32C native code using SSE4.2 instructions

["Tsz Wo (Nicholas), SZE (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HADOOP-7446?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13083968#comment-13083968 ] 

Tsz Wo (Nicholas), SZE commented on HADOOP-7446:
------------------------------------------------

In the code below, rbx should be ebx.
{code}
+  asm("pushq %%rbx\n\t" /* save %rbx */
+      "cpuid\n\t"
+      "movl %%ebx, %[ebx]\n\t" /* save what cpuid just put in %ebx */
+      "popq %%rbx" : "=a"(eax), [ebx] "=r"(ebx), "=c"(ecx), "=d"(edx) : "a" (eax_in)
{code}


> 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
>
>
> 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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