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From "Michael Ho (Code Review)" <ger...@cloudera.org>
Subject [Impala-ASF-CR] IMPALA-4164: Use inline hints instead of always-inline
Date Fri, 26 May 2017 00:19:50 GMT
Michael Ho has uploaded a new patch set (#6).

Change subject: IMPALA-4164: Use inline hints instead of always-inline
......................................................................

IMPALA-4164: Use inline hints instead of always-inline

When generating IR functions during codegen, we used to
always tag the functions with the "AlwaysInline" attribute.
That potentially leads to excessive inlining, leading to
very long optimization / compilation time with marginal
performance benefit at runtime. One of the reasons for doing
it was that the "target-cpu" and "target-features" attributes
are missing in the generated IR functions so the LLVM inliner
considers them incompatible with the cross-compiled functions.
As a result, the inliner will not inline the generated IR
functions into cross-compiled functions unless we put the
"AlwaysInline" attributes with the generated IR functions.

This change fixes the problem above by setting the "target-cpu"
and "target-features" attributes of all IR functions to match
that of of the host's CPUs so both generated IR functions and
cross-compiled functions will have the same values for those
attributes. With these attributes set, we now switch to using
"InlineHint" in place of "AlwaysInline" and let LLVM make the
decision of whether it's sensible to inline a function. With
this change, the codegen time of a query with a long predicate
went from 15s to 4s and the overall runtime went from 19s to 8s.

Change-Id: I2d87ae8d222b415587e7320cb9072e4a8d6615ce
---
M be/src/codegen/llvm-codegen.cc
M be/src/codegen/llvm-codegen.h
A testdata/workloads/targeted-perf/queries/primitive_long_predicate.test
3 files changed, 211 insertions(+), 11 deletions(-)


  git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/41/6941/6
-- 
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Gerrit-MessageType: newpatchset
Gerrit-Change-Id: I2d87ae8d222b415587e7320cb9072e4a8d6615ce
Gerrit-PatchSet: 6
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Michael Ho <kwho@cloudera.com>
Gerrit-Reviewer: Michael Ho <kwho@cloudera.com>
Gerrit-Reviewer: Tim Armstrong <tarmstrong@cloudera.com>

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