Michael Smith has posted comments on this change. ( 
http://gerrit.cloudera.org:8080/24940 )

Change subject: IMPALA-11917: Upgrade to GCC 15 and LLVM 22
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Patch Set 15:

> Patch Set 14:
>
> > Patch Set 14:
> >
> > > Patch Set 14:
> > >
> > > > (2 comments)
> > >
> > > Interesting, on the whole the diff seems to be around noise level, but 
> > > some queries (TPCDS-Q99) have serious diff. This is a very short query, 
> > > my guess is that the comes from codegen compilation times.
> >
> > TPCDS-Q99 sees a 10% reduction with and without codegen. So I don't think 
> > codegen time is much of a factor.
> >
> > The main difference seems to be in execution time of the generated code 
> > itself during joins and aggregation. I'll see if I can reproduce locally 
> > and do some more targeted analysis. I think the difference is small enough 
> > overall we could handle it in a follow-up ticket.
>
> Found an attribute that affects inlining, testing it out.

Setting tune-cpu fixed a lot of the regression in Q99, and I added an 
additional patch that optimizes simple SlotRef reads that preserves the LLVM 5 
code generation there. That should bring Q99 inline, and maybe improve some 
others. Re-running with both changes at 
https://jenkins.impala.io/job/perf-AB-test-ub2204/48/.


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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: I7dda730fa98ebe3825969265627a560b0c3095f9
Gerrit-Change-Number: 24940
Gerrit-PatchSet: 15
Gerrit-Owner: Michael Smith <[email protected]>
Gerrit-Reviewer: Balazs Hevele <[email protected]>
Gerrit-Reviewer: Csaba Ringhofer <[email protected]>
Gerrit-Reviewer: Impala Public Jenkins <[email protected]>
Gerrit-Reviewer: Joe McDonnell <[email protected]>
Gerrit-Reviewer: Laszlo Gaal <[email protected]>
Gerrit-Reviewer: Michael Smith <[email protected]>
Gerrit-Comment-Date: Thu, 01 Oct 2026 18:39:53 +0000
Gerrit-HasComments: No

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