peterxcli commented on PR #5725:
URL: 
https://github.com/apache/datafusion-comet/pull/5725#issuecomment-5578031237

   @sunchao Added the requested old-dispatcher/native/pure-Spark comparison in 
7e8f30a37 and published both runs in the PR description. The long-array 
fixture, release library, batch size and JVM settings are matched. The old arm 
uses the original serializer from the PR's parent, and the benchmark checks 
dispatcher activity as well as physical plans.
   
   For literal separators, native averaged 171/172 ms versus the old 
dispatcher's 176/185 ms. For column separators, it averaged 133/140 ms versus 
173/170 ms. The first native literal run had a 75 ms standard deviation, so the 
small literal improvement is uncertain. I propose retaining native array 
routing based on this comparison with the old default. Pure Spark still 
performs better on several long-array measurements; its controls and the timing 
variance are included in the table.
   
   For the remaining gap to pure Spark, the plan is to profile allocation and 
copying, then test an upstream output-capacity estimate against the current 
reservation on both short and long inputs. Profiling will establish whether 
reallocations explain the gap; scalar expansion and list-row slicing are the 
next candidates to examine. The benchmark path checks, compilation and semantic 
lint passed.
   


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