Daniel Becker has posted comments on this change. ( 
http://gerrit.cloudera.org:8080/13807 )

Change subject: IMPALA-8741: Speed up bit unpacking by vectorisation
......................................................................


Patch Set 12:

(2 comments)

http://gerrit.cloudera.org:8080/#/c/13807/4/be/src/util/bit-packing.h
File be/src/util/bit-packing.h:

http://gerrit.cloudera.org:8080/#/c/13807/4/be/src/util/bit-packing.h@67
PS4, Line 67:   template <typename OutType, bool VECTORIZE = true>
> I made measurements and a graph and added it to the Jira issue:
Csaba had an idea that we could get rid of the VECTORIZE parameter completely 
and test the non-vectorised code path by disabling the CPU flags in CpuInfo in 
the tests.


http://gerrit.cloudera.org:8080/#/c/13807/4/be/src/util/bit-packing.inline.h
File be/src/util/bit-packing.inline.h:

http://gerrit.cloudera.org:8080/#/c/13807/4/be/src/util/bit-packing.inline.h@84
PS4, Line 84:   if (LIKELY((std::is_same<OutType, uint8_t>::value
> Does it even make sense to unpack values into a different type outside of t
We also use bool somewhere, at least bit-packing.cc instantiates the methods 
with bool.



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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: I9e452a547973778bbd8d768c608e1a32e948f947
Gerrit-Change-Number: 13807
Gerrit-PatchSet: 12
Gerrit-Owner: Daniel Becker <[email protected]>
Gerrit-Reviewer: Csaba Ringhofer <[email protected]>
Gerrit-Reviewer: Daniel Becker <[email protected]>
Gerrit-Reviewer: Impala Public Jenkins <[email protected]>
Gerrit-Reviewer: Tim Armstrong <[email protected]>
Gerrit-Comment-Date: Mon, 22 Jul 2019 11:47:06 +0000
Gerrit-HasComments: Yes

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