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By varying the generic type, nested calls can allocate a new per-instruction-cache per frame. Calls can be 1024 deep and a function can have 64K entries. The per-instruction cache is sparse, as most instructions will not have an entry. A hash will have more cost for insert/get but this is O(1) and will be very fast. We add a benchmark which shows that the HashMap -> Vec makes no difference in performance.
seanyoung
requested review from
0xIcarus,
Primata,
ganymedio and
musitdev
as code owners
August 20, 2026 10:44
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Description
By varying the generic type, nested calls can allocate a new per-instruction-cache per frame. Calls can be 1024 deep and a function can have 64K entries.
The per-instruction cache is sparse, as most instructions will not have an entry. A hash will have more cost for insert/get but this is O(1) and will be very fast. We add a benchmark which shows that the HashMap -> Vec makes no difference in performance.
Different fix for aptos-labs#20341
How Has This Been Tested?
See included bench mark and regular VM testing.
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Type of Change
Which Components or Systems Does This Change Impact?
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