Tim Armstrong has posted comments on this change.
Change subject: IMPALA-4058: ByteSwap256 assumed memory was 16-byte aligned.
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Patch Set 5: Code-Review+1
(1 comment)
I also extended the microbenchmark to test perf when loads and stores were
actually misaligned (not just using the different instruction). AVX2 is still
significantly faster than SSE. I'll post a CR with that benchmark change
separately.
I0901 13:47:02.025802 4956 bswap-benchmark.cc:122] Machine Info: Intel(R)
Core(TM) i7-4790 CPU @ 3.60GHz
ByteSwap benchmark alignment=0:Function iters/ms 10%ile 50%ile
90%ile 10%ile 50%ile 90%ile
(relative) (relative) (relative)
---------------------------------------------------------------------------------------------------------
FastScalar 881 1.08e+03 1.14e+03
1X 1X 1X
SSSE3 9.33e+03 1.02e+04 1.03e+04
10.6X 9.46X 9.03X
AVX2 3.43e+04 3.78e+04 3.84e+04
38.9X 35.2X 33.7X
SIMD 3.27e+04 3.78e+04 3.83e+04
37.1X 35.2X 33.6X
ByteSwap benchmark alignment=1:Function iters/ms 10%ile 50%ile
90%ile 10%ile 50%ile 90%ile
(relative) (relative) (relative)
---------------------------------------------------------------------------------------------------------
FastScalar 1e+03 1.08e+03 1.15e+03
1X 1X 1X
SSSE3 8.67e+03 9.01e+03 9.11e+03
8.66X 8.31X 7.95X
AVX2 2.62e+04 2.75e+04 2.77e+04
26.2X 25.4X 24.2X
SIMD 2.56e+04 2.72e+04 2.75e+04
25.6X 25.1X 24X
http://gerrit.cloudera.org:8080/#/c/4205/5/be/src/util/bit-util-test.cc
File be/src/util/bit-util-test.cc:
PS5, Line 116: o
or
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Gerrit-MessageType: comment
Gerrit-Change-Id: I39b2b47bb717d5ac9727512a24fcf8a8a6a8dcc6
Gerrit-PatchSet: 5
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Jim Apple <[email protected]>
Gerrit-Reviewer: Dan Hecht <[email protected]>
Gerrit-Reviewer: Jim Apple <[email protected]>
Gerrit-Reviewer: Tim Armstrong <[email protected]>
Gerrit-Reviewer: Youwei Wang <[email protected]>
Gerrit-HasComments: Yes
