Marcel Kornacker has posted comments on this change.

Change subject: IMPALA-2809: Improve ByteSwap with builtin function or SSSE3 or 
AVX2.
......................................................................


Patch Set 38:

(12 comments)

http://gerrit.cloudera.org:8080/#/c/3081/38/be/src/util/bit-util-test.cc
File be/src/util/bit-util-test.cc:

Line 99: void TestByteswapSimdUnit(const int64_t CpuFlag) {
name formatting


Line 192:   if (LIKELY(CpuInfo::IsSupported(CpuInfo::SSSE3))) {
remove likely, this is not performance-critical


Line 203:     TestByteswapSimdUnit(CpuInfo::SSSE3);
we already did this above


Line 211:   for (int i = 0; i <= 32; ++i) {
single line


http://gerrit.cloudera.org:8080/#/c/3081/38/be/src/util/bit-util.cc
File be/src/util/bit-util.cc:

Line 19:   // ByteSwapScalarLoop is only used in bit-util.cc, so put it in this 
anonymous
make it static instead? or get remove the extra level of indentation.


Line 25:     for (int i = 0; i < len; ++i) {
single line


Line 135: // This constant is concluded from the definition of _mm_set_epi8;
included?


Line 144:     _mm_loadu_si128(reinterpret_cast<const __m128i*>(src)), 
mask128i));
indent 4 spaces (and elsewhere)


Line 149: inline void SimdByteSwap::ByteSwapAVX2_Unit(uint8_t* dst, const 
uint8_t* src) {
should this be called ByteSwap256 or something like that? i had no idea what 
exactly this does.


http://gerrit.cloudera.org:8080/#/c/3081/38/be/src/util/bit-util.h
File be/src/util/bit-util.h:

Line 244: // Declaration for the namespace of SIMD byteswap utilities
we don't use that elsewhere. make it a class with static functions instead.


Line 246:   // Extra type declarations
i don't understand this comment


Line 249:   // Declaration for scalar utility functions
don't prefix the comment for a declaration with 'Declaration for'. also, 
there's only one.

this function comment doesn't describe what the caller needs to know 
(externally observable behavior; roles of params).


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Gerrit-MessageType: comment
Gerrit-Change-Id: I392ed5a8d5683f30f161282c228c1aedd7b648c1
Gerrit-PatchSet: 38
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]>
Gerrit-HasComments: Yes

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