Youwei Wang has posted comments on this change. Change subject: IMPALA-2809: Improve ByteSwap with builtin function or SSE or AVX2. ......................................................................
Patch Set 5: (1 comment) http://gerrit.cloudera.org:8080/#/c/3081/5/be/src/util/bit-util.inline.h File be/src/util/bit-util.inline.h: Line 174: static const FuncPointer SIMDFuncTable[2] = {ByteSwapSSE_Unit, ByteSwapAVX2_Unit}; > Sorry, I meant an actual template parameter. Hi Jim. Thank you so much for your clarification. As you can see here, the internal code of ByteSwapSSE_Unit and ByteSwapAVX2_Unit can not be distinguished easily by a parameter except using a branch, which is known harmful to the performance. This case is different from previous ByteSwapSSE and ByteSwapAVX2 since they are essentially polynomial expression. We can control the logic flow using a single parameter. I am not sure this explaination is satisfying enough. You are welcomed to point out any mistake I have made here. Thank you again. :) -- To view, visit http://gerrit.cloudera.org:8080/3081 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-MessageType: comment Gerrit-Change-Id: I392ed5a8d5683f30f161282c228c1aedd7b648c1 Gerrit-PatchSet: 5 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
