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Fix tail effect on GPUs - #2558

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dennisYatunin wants to merge 1 commit into
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dy/tail_effect
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Fix tail effect on GPUs#2558
dennisYatunin wants to merge 1 commit into
mainfrom
dy/tail_effect

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@dennisYatunin

@dennisYatunin dennisYatunin commented Jul 28, 2026

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This PR extends max_resident_blocks to account for register pressure and shared memory requirements, fixing the "tail effect" problem that was introduced in #2522 for 64-level pointwise kernels (see this comment for details).

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@imreddyTeja

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This does fix the tail effect, but it does not give the 50% speedup that ncu thought it would. It still says the average active warps increased by 1. It does give a small speed up. I'm a bit concerned about how this will impact ClimaLand though. I'd guess the extra dictionary usage might impact latency

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