Profile: simplify Memory in heap snapshot#60930
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topolarity merged 1 commit intoJuliaLang:masterfrom Mar 6, 2026
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I took a closer look and it turns out I was wrong about this bug. This memory was being accounted for in the snapshot after all, but it was being put into secret "hidden" edges. This PR now moves those bytes from the "hidden" edge to the Re-requesting review given the major re-work. |
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If I recall correctly, I might have suggested this in case the memory buffer wrapped is aliased between multiple different objects. |
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| // Memory's that are string-owned or point to foreign memory have | ||
| // explicit snapshot edges to pointee data. Otherwise the array | ||
| // contents are treated as part of the Memory itself. | ||
| self_size += jl_genericmemory_nbytes(mem); |
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This makes `Memory` more intuitive to interpret in heap snapshots.
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Why do the indices in the screenshot appear to be random numbers? |
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It's being sorted and it's a very large array, so those are the largest elements |
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Ah, of course. |
This was referenced Feb 25, 2026
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`Memory` somewhat awkwardly encodes the size of its data in an "internal" edge in the heap snapshot. This is reasonable for String-owned Memory's, but it is pointlessly complex / confusing for GC-managed and inline-allocated Memory data arrays. This changes those bytes to be directly attributed to the `Memory` itself instead. Also fix a bug that caused all Memory indices to be `[0]` in the heap snapshot. (cherry picked from commit 7f14dc3)
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Memorysomewhat awkwardly encodes the size of its data in an "internal" edge in the heap snapshot.This is reasonable for String-owned Memory's, but it is pointlessly complex / confusing for GC-managed and inline-allocated Memory data arrays. This changes those bytes to be directly attributed to the
Memoryitself instead.Also fix a bug that caused all Memory indices to be
[0]in the heap snapshot.Before:
After:
