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From "Youwei Wang (Code Review)" <>
Subject [Impala-CR](cdh5-trunk) IMPALA-2809: Improve ByteSwap with builtin function or SSSE3 or AVX2.
Date Thu, 16 Jun 2016 14:24:47 GMT
Youwei Wang has posted comments on this change.

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

Patch Set 21:

Hi Jim. 
If you don’t mind, I want to show you some performance data of the API
StringVal StringFunctions::Reverse(FunctionContext* context, const StringVal& str) in before/after it utilizes the BitUtil::ByteSwap(SIMD) routine.

The experiment setup is:
Hardware: : Intel(R) Core(TM) i5-4460  CPU@3.20GHz
Testdata: lineitem.tbl file from TPC-H dbgen using scale=10; whose size is 7.3G. It has 59986052
Testquery: select reverse(l_comment) from tpch1.lineitem;

Experiment result:
Using std::reverse_copy: Fetched 59986052 row(s) in 1214.63s
Using BitUtil::ByteSwap(SIMD): Fetched 59986052 row(s) in 1188.57s
We do get some performance improvement here considering console output and HDFS file reading
takes most of the runtime. 

I am not sure whether such result is persuasive enough. Please feel free to tell me your idea
about this. Thank you.

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Gerrit-MessageType: comment
Gerrit-Change-Id: I392ed5a8d5683f30f161282c228c1aedd7b648c1
Gerrit-PatchSet: 21
Gerrit-Project: Impala
Gerrit-Branch: cdh5-trunk
Gerrit-Owner: Youwei Wang <>
Gerrit-Reviewer: Alex Behm <>
Gerrit-Reviewer: Jim Apple <>
Gerrit-Reviewer: Marcel Kornacker <>
Gerrit-Reviewer: Mostafa Mokhtar <>
Gerrit-Reviewer: Tim Armstrong <>
Gerrit-Reviewer: Youwei Wang <>
Gerrit-HasComments: No

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