Jim Apple has posted comments on this change.

Change subject: IMPALA-2809: Improve ByteSwap with builtin function or SSE or 
AVX2.
......................................................................


Patch Set 3:

(2 comments)

http://gerrit.cloudera.org:8080/#/c/3081/3/be/src/benchmarks/bswap-benchmark.cc
File be/src/benchmarks/bswap-benchmark.cc:

Line 156:   if (num_bytes == 4) {
> I think more than comments will be necessary. Can you reduce the repetition
I never received a reply to this.


http://gerrit.cloudera.org:8080/#/c/3081/3/be/src/util/bit-util.inline.h
File be/src/util/bit-util.inline.h:

Line 140:   const __m128i mask = _mm_set_epi8(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 
11, 12, 13, 14,
> Maybe I haven't explained it clearly enough. The      __attribute__ only 
> works 
Pseudocode:

    #ifdef SOME_MACRO_INDICATING_AVX_SUPPORT
        const __m128i mask = ...
        inline void ByteSwapSSE_Unit(...
    #endif

Have you checked in assembly what the effect of making this static are? How 
about in the actual performance numbers?


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Gerrit-MessageType: comment
Gerrit-Change-Id: I392ed5a8d5683f30f161282c228c1aedd7b648c1
Gerrit-PatchSet: 3
Gerrit-Project: Impala
Gerrit-Branch: cdh5-trunk
Gerrit-Owner: Youwei Wang <[email protected]>
Gerrit-Reviewer: Alex Behm <[email protected]>
Gerrit-Reviewer: Jim Apple <[email protected]>
Gerrit-Reviewer: Marcel Kornacker <[email protected]>
Gerrit-Reviewer: Mostafa Mokhtar <[email protected]>
Gerrit-Reviewer: Tim Armstrong <[email protected]>
Gerrit-Reviewer: Youwei Wang <[email protected]>
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